ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS#9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS #9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
alamb Mar 31, 2021
e3f1410
use into() rather than build()
alamb Mar 31, 2021
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20 changes: 12 additions & 8 deletions rust/datafusion/src/catalog/information_schema.rs
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Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
}

let mem_table= builder.build();
let mem_table: MemTable = builder.into();

Arc::new(mem_table)
}
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
}
}

let mem_table= builder.build();
let mem_table: MemTable = builder.into();

Arc::new(mem_table)
}
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
self.table_names.append_value(table_name.as_ref()).unwrap();
self.table_types.append_value("VIEW").unwrap();
}
}

fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
fn from(value: InformationSchemaTablesBuilder) -> MemTable {
let schema = Schema::new(vec![
Field::new("table_catalog", DataType::Utf8, false),
Field::new("table_schema", DataType::Utf8, false),
Field::new("table_name", DataType::Utf8, false),
Field::new("table_type", DataType::Utf8, false),
]);

let Self {
let InformationSchemaTablesBuilder {
mut catalog_names,
mut schema_names,
mut table_names,
mut table_types,
} = self;
} = value;

let schema = Arc::new(schema);
let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
self.datetime_precisions.append_option(None).unwrap();
self.interval_types.append_null().unwrap();
}
}

fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
let schema = Schema::new(vec![
Field::new("table_catalog", DataType::Utf8, false),
Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
Field::new("interval_type", DataType::Utf8, false),
]);

let Self {
let InformationSchemaColumnsBuilder {
mut catalog_names,
mut schema_names,
mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
mut numeric_scales,
mut datetime_precisions,
mut interval_types,
} = self;
} = value;

let schema = Arc::new(schema);
let batch = RecordBatch::try_new(
Expand Down
144 changes: 144 additions & 0 deletions rust/datafusion/src/execution/context.rs
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Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
assert_batches_sorted_eq!(expected, &result);
}

#[tokio::test]
async fn information_schema_show_columns_no_information_schema() {
let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

ctx.register_table("t", table_with_sequence(1, 1).unwrap())
.unwrap();

let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
.await
.unwrap_err();

assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
}

#[tokio::test]
async fn information_schema_show_columns_like_where() {
let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

ctx.register_table("t", table_with_sequence(1, 1).unwrap())
.unwrap();

let expected =
"Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
.await
.unwrap_err();
assert_eq!(err.to_string(), expected);

let err =
plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
.await
.unwrap_err();
assert_eq!(err.to_string(), expected);
}

#[tokio::test]
async fn information_schema_show_columns() {
let mut ctx = ExecutionContext::with_config(
ExecutionConfig::new().with_information_schema(true),
);

ctx.register_table("t", table_with_sequence(1, 1).unwrap())
.unwrap();

let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
.await
.unwrap();

let expected = vec![
"+---------------+--------------+------------+-------------+-----------+-------------+",
"| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
"+---------------+--------------+------------+-------------+-----------+-------------+",
"| datafusion | public | t | i | Int32 | YES |",
"+---------------+--------------+------------+-------------+-----------+-------------+",
];
assert_batches_sorted_eq!(expected, &result);

let result = plan_and_collect(&mut ctx, "SHOW columns from t")
.await
.unwrap();
assert_batches_sorted_eq!(expected, &result);

// This isn't ideal but it is consistent behavior for `SELECT * from T`
let err = plan_and_collect(&mut ctx, "SHOW columns from T")
.await
.unwrap_err();
assert_eq!(
err.to_string(),
"Error during planning: Unknown relation for SHOW COLUMNS: T"
);
}

// test errors with WHERE and LIKE
#[tokio::test]
async fn information_schema_show_columns_full_extended() {
let mut ctx = ExecutionContext::with_config(
ExecutionConfig::new().with_information_schema(true),
);

ctx.register_table("t", table_with_sequence(1, 1).unwrap())
.unwrap();

let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
.await
.unwrap();
let expected = vec![

"+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
"| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
"+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
"| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
"+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

];
assert_batches_sorted_eq!(expected, &result);

let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
.await
.unwrap();
assert_batches_sorted_eq!(expected, &result);
}

#[tokio::test]
async fn information_schema_show_table_table_names() {
let mut ctx = ExecutionContext::with_config(
ExecutionConfig::new().with_information_schema(true),
);

ctx.register_table("t", table_with_sequence(1, 1).unwrap())
.unwrap();

let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
.await
.unwrap();

let expected = vec![
"+---------------+--------------+------------+-------------+-----------+-------------+",
"| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
"+---------------+--------------+------------+-------------+-----------+-------------+",
"| datafusion | public | t | i | Int32 | YES |",
"+---------------+--------------+------------+-------------+-----------+-------------+",
];
assert_batches_sorted_eq!(expected, &result);

let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
.await
.unwrap();
assert_batches_sorted_eq!(expected, &result);

let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
.await
.unwrap_err();
assert_eq!(
err.to_string(),
"Error during planning: Unknown relation for SHOW COLUMNS: t2"
);

let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
.await
.unwrap_err();
assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
}

#[tokio::test]
async fn show_unsupported() {
let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down
87 changes: 77 additions & 10 deletions rust/datafusion/src/sql/planner.rs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
} => self.explain_statement_to_plan(*verbose, &statement),
Statement::Query(query) => self.query_to_plan(&query),
Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
Statement::ShowColumns {
extended,
full,
table_name,
filter,
} => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
_ => Err(DataFusionError::NotImplemented(
"Only SELECT statements are implemented".to_string(),
)),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
// Special case SHOW TABLES
let variable = ObjectName(variable.to_vec()).to_string();
if variable.as_str().eq_ignore_ascii_case("tables") {
let tables_reference = TableReference::Partial {
schema: "information_schema",
table: "tables",
};
if self
.schema_provider
.get_table_provider(tables_reference)
.is_some()
{
if self.has_table("information_schema", "tables") {
let rewrite =
DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
)))
}
}

fn show_columns_to_plan(
&self,
extended: bool,
full: bool,
table_name: &ObjectName,
filter: Option<&ShowStatementFilter>,
) -> Result<LogicalPlan> {
if filter.is_some() {
return Err(DataFusionError::Plan(
"SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
));
}

if !self.has_table("information_schema", "columns") {
return Err(DataFusionError::Plan(
"SHOW COLUMNS is not supported unless information_schema is enabled"
.to_string(),
));
}

if self
.schema_provider
.get_table_provider(table_name.try_into()?)
.is_none()
{
return Err(DataFusionError::Plan(format!(
"Unknown relation for SHOW COLUMNS: {}",
table_name
)));
}

// Figure out the where clause
let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
let where_clause = table_name
.0
.iter()
.rev()

@DandandanDandandanApr 1, 2021•
edited
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Why rev and not listing the items in columns in reverse?

@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema

So you have to handle the case of

table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),

So this formulation was what I could come up with that would match them up to the information_schema column names

I am open to other ways of doing it as well if you have suggestions

@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way

.zip(columns)
.map(|(ident, column_name)| {
format!(r#"{} = '{}'"#, column_name, ident.to_string())
})
.collect::<Vec<_>>()
.join(" AND ");

// treat both FULL and EXTENDED as the same
let select_list = if full || extended {
"*"
} else {
"table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
};

let query = format!(
"SELECT {} FROM information_schema.columns WHERE {}",
select_list, where_clause
);

let rewrite = DFParser::parse_sql(&query)?;
self.statement_to_plan(&rewrite[0])
}

/// Return true if there is a table provider available for "schema.table"
fn has_table(&self, schema: &str, table: &str) -> bool {
let tables_reference = TableReference::Partial { schema, table };
self.schema_provider
.get_table_provider(tables_reference)
.is_some()
}
}

/// Remove join expressions from a filter expression
Expand Down
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS#9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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8722430

ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

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Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS#9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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8722430

ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

edited

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS#9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS#9866

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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8722430

ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS
#9866
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ARROW-12109: [Rust][DataFusion] Implement SHOW COLUMNS


alamb Mar 31, 2021
e3f1410

use into() rather than build()


alamb Mar 31, 2021

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20 changes: 12 additions & 8 deletions
rust/datafusion/src/catalog/information_schema.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -115,7 +115,7 @@ impl InformationSchemaProvider {
 builder.add_system_table(&catalog_name, INFORMATION_SCHEMA, COLUMNS);
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -148,7 +148,7 @@ impl InformationSchemaProvider {
 }
 }

 let mem_table= builder.build();
 let mem_table: MemTable = builder.into();

 Arc::new(mem_table)
 }
Expand DownExpand Up@@ -231,21 +231,23 @@ impl InformationSchemaTablesBuilder {
 self.table_names.append_value(table_name.as_ref()).unwrap();
 self.table_types.append_value("VIEW").unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaTablesBuilder> for MemTable {
 fn from(value: InformationSchemaTablesBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
 Field::new("table_name", DataType::Utf8, false),
 Field::new("table_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaTablesBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
 mut table_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand DownExpand Up@@ -422,8 +424,10 @@ impl InformationSchemaColumnsBuilder {
 self.datetime_precisions.append_option(None).unwrap();
 self.interval_types.append_null().unwrap();
 }
}

 fn build(self) -> MemTable {
impl From<InformationSchemaColumnsBuilder> for MemTable {
 fn from(value: InformationSchemaColumnsBuilder) -> MemTable {
 let schema = Schema::new(vec![
 Field::new("table_catalog", DataType::Utf8, false),
 Field::new("table_schema", DataType::Utf8, false),
Expand All@@ -442,7 +446,7 @@ impl InformationSchemaColumnsBuilder {
 Field::new("interval_type", DataType::Utf8, false),
 ]);

 let Self {
 let InformationSchemaColumnsBuilder {
 mut catalog_names,
 mut schema_names,
 mut table_names,
Expand All@@ -458,7 +462,7 @@ impl InformationSchemaColumnsBuilder {
 mut numeric_scales,
 mut datetime_precisions,
 mut interval_types,
 } = self;
 } = value;

 let schema = Arc::new(schema);
 let batch = RecordBatch::try_new(
Expand Down

144 changes: 144 additions & 0 deletions
rust/datafusion/src/execution/context.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2253,6 +2253,150 @@ mod tests {
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_columns_no_information_schema() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap_err();

 assert_eq!(err.to_string(), "Error during planning: SHOW COLUMNS is not supported unless information_schema is enabled");
 }

 #[tokio::test]
 async fn information_schema_show_columns_like_where() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let expected =
 "Error during planning: SHOW COLUMNS with WHERE or LIKE is not supported";

 let err = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t LIKE 'f'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);

 let err =
 plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t WHERE column_name = 'bar'")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), expected);
 }

 #[tokio::test]
 async fn information_schema_show_columns() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 // This isn't ideal but it is consistent behavior for `SELECT * from T`
 let err = plan_and_collect(&mut ctx, "SHOW columns from T")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: T"
 );
 }

 // test errors with WHERE and LIKE
 #[tokio::test]
 async fn information_schema_show_columns_full_extended() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW FULL COLUMNS FROM t")
 .await
 .unwrap();
 let expected = vec![

 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| table_catalog | table_schema | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",
 "| datafusion | public | t | i | 0 | | YES | Int32 | | | 32 | 2 | | | |",
 "+---------------+--------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+",

 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW EXTENDED COLUMNS FROM t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);
 }

 #[tokio::test]
 async fn information_schema_show_table_table_names() {
 let mut ctx = ExecutionContext::with_config(
 ExecutionConfig::new().with_information_schema(true),
 );

 ctx.register_table("t", table_with_sequence(1, 1).unwrap())
 .unwrap();

 let result = plan_and_collect(&mut ctx, "SHOW COLUMNS FROM public.t")
 .await
 .unwrap();

 let expected = vec![
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| table_catalog | table_schema | table_name | column_name | data_type | is_nullable |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 "| datafusion | public | t | i | Int32 | YES |",
 "+---------------+--------------+------------+-------------+-----------+-------------+",
 ];
 assert_batches_sorted_eq!(expected, &result);

 let result = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t")
 .await
 .unwrap();
 assert_batches_sorted_eq!(expected, &result);

 let err = plan_and_collect(&mut ctx, "SHOW columns from t2")
 .await
 .unwrap_err();
 assert_eq!(
 err.to_string(),
 "Error during planning: Unknown relation for SHOW COLUMNS: t2"
 );

 let err = plan_and_collect(&mut ctx, "SHOW columns from datafusion.public.t2")
 .await
 .unwrap_err();
 assert_eq!(err.to_string(), "Error during planning: Unknown relation for SHOW COLUMNS: datafusion.public.t2");
 }

 #[tokio::test]
 async fn show_unsupported() {
 let mut ctx = ExecutionContext::with_config(ExecutionConfig::new());
Expand Down

87 changes: 77 additions & 10 deletions
rust/datafusion/src/sql/planner.rs

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -46,7 +46,8 @@ use crate::prelude::JoinType;
use sqlparser::ast::{
 BinaryOperator, DataType as SQLDataType, DateTimeField, Expr as SQLExpr, FunctionArg,
 Ident, Join, JoinConstraint, JoinOperator, ObjectName, Query, Select, SelectItem,
 SetExpr, SetOperator, TableFactor, TableWithJoins, UnaryOperator, Value,
 SetExpr, SetOperator, ShowStatementFilter, TableFactor, TableWithJoins,
 UnaryOperator, Value,
};
use sqlparser::ast::{ColumnDef as SQLColumnDef, ColumnOption};
use sqlparser::ast::{OrderByExpr, Statement};
Expand DownExpand Up@@ -100,6 +101,12 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 } => self.explain_statement_to_plan(*verbose, &statement),
 Statement::Query(query) => self.query_to_plan(&query),
 Statement::ShowVariable { variable } => self.show_variable_to_plan(&variable),
 Statement::ShowColumns {
 extended,
 full,
 table_name,
 filter,
 } => self.show_columns_to_plan(*extended, *full, table_name, filter.as_ref()),
 _ => Err(DataFusionError::NotImplemented(
 "Only SELECT statements are implemented".to_string(),
 )),
Expand DownExpand Up@@ -1280,15 +1287,7 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 // Special case SHOW TABLES
 let variable = ObjectName(variable.to_vec()).to_string();
 if variable.as_str().eq_ignore_ascii_case("tables") {
 let tables_reference = TableReference::Partial {
 schema: "information_schema",
 table: "tables",
 };
 if self
 .schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 {
 if self.has_table("information_schema", "tables") {
 let rewrite =
 DFParser::parse_sql("SELECT * FROM information_schema.tables;")?;
 self.statement_to_plan(&rewrite[0])
Expand All@@ -1305,6 +1304,74 @@ impl<'a, S: ContextProvider> SqlToRel<'a, S> {
 )))
 }
 }

 fn show_columns_to_plan(
 &self,
 extended: bool,
 full: bool,
 table_name: &ObjectName,
 filter: Option<&ShowStatementFilter>,
 ) -> Result<LogicalPlan> {
 if filter.is_some() {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS with WHERE or LIKE is not supported".to_string(),
 ));
 }

 if !self.has_table("information_schema", "columns") {
 return Err(DataFusionError::Plan(
 "SHOW COLUMNS is not supported unless information_schema is enabled"
 .to_string(),
 ));
 }

 if self
 .schema_provider
 .get_table_provider(table_name.try_into()?)
 .is_none()
 {
 return Err(DataFusionError::Plan(format!(
 "Unknown relation for SHOW COLUMNS: {}",
 table_name
 )));
 }

 // Figure out the where clause
 let columns = vec!["table_name", "table_schema", "table_catalog"].into_iter();
 let where_clause = table_name
 .0
 .iter()
 .rev()
@DandandanDandandanApr 1, 2021•

edited

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Why rev and not listing the items in columns in reverse?
@alambalambApr 1, 2021

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I was thinking because the identifier may not have a table_catalog or table_schema
So you have to handle the case of
table_name (position 0)
table_name (position 1), schema_name (postition 0)
table_name (postition 2), schema_name (postition 1), catalog_name (position 0),
So this formulation was what I could come up with that would match them up to the information_schema column names
I am open to other ways of doing it as well if you have suggestions
@DandandanDandandanApr 5, 2021

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You are totally right 👍 I don't have a suggestion for an easier way
 .zip(columns)
 .map(|(ident, column_name)| {
 format!(r#"{} = '{}'"#, column_name, ident.to_string())
 })
 .collect::<Vec<_>>()
 .join(" AND ");

 // treat both FULL and EXTENDED as the same
 let select_list = if full || extended {
 "*"
 } else {
 "table_catalog, table_schema, table_name, column_name, data_type, is_nullable"
 };

 let query = format!(
 "SELECT {} FROM information_schema.columns WHERE {}",
 select_list, where_clause
 );

 let rewrite = DFParser::parse_sql(&query)?;
 self.statement_to_plan(&rewrite[0])
 }

 /// Return true if there is a table provider available for "schema.table"
 fn has_table(&self, schema: &str, table: &str) -> bool {
 let tables_reference = TableReference::Partial { schema, table };
 self.schema_provider
 .get_table_provider(tables_reference)
 .is_some()
 }
}

/// Remove join expressions from a filter expression
Expand Down