SQL Proficiency 🚀

Welcome to the SQL Proficiency Document! This document serves to illustrate proficiency in the SQL coding lanuage.. Let's dive in! 💻

Table of Contents 📑

1. Introduction
2. Basic Queries
3. Advanced Queries
4. Data Manipulation
5. Joins & Unions
6. Aggregation
7. Window Functions
8. Indexes and Optimization
9. Transactions
10. Stored Procedures
11. Data Modeling
12. Bonus Tips
13. Resources

Introduction 🌐

SQL (Structured Query Language) is the language of databases. Whether you're fetching data or transforming it, SQL is your go-to tool. Let's explore its depths!

Basic Queries 🕵️‍♂️

Selecting Columns

SELECT column1, column2
FROM table
WHERE condition;

Filtering Results

SELECT*FROM table
WHERE column ='value';

Advanced Queries 🚀

Subqueries

SELECT*FROM table
WHERE column IN (SELECT column FROM another_table);

Common Table Expressions

WITH cte_name AS (
SELECT column
FROM table
)
SELECT*FROM cte_name;

Data Manipulation ✨

Inserting Data

INSERT INTO table (column1, column2)
VALUES ('value1', 'value2');

Updating Data

UPDATE table
SET column ='new_value'WHERE condition;

Joins and Unions 🔗

Inner join

SELECT*FROM table1
JOIN table2 ONtable1.column=table2.column;

Union

SELECT column FROM table1
UNIONSELECT column FROM table2;

Aggregation 📊

Group By

SELECT column, COUNT(*)
FROM table
GROUP BY column;

Having clause

SELECT column, COUNT(*)
FROM table
GROUP BY column
HAVINGCOUNT(*) >1;

Window Functions 🪟

Rank and Partition (could also be Row_Number)

SELECT column, RANK() OVER (PARTITION BY category ORDER BY value DESC) AS ranking
FROM table;

Indexes and Optimization ⚙️

Indexing

CREATEINDEXindex_nameON table (column);

Query Optimization

EXPLAIN SELECT column
FROM table
WHERE condition;

Transactions 🔄

BEGIN TRANSACTION;
-- SQL Statements hereCOMMIT;

Stored Procedures 📦

CREATE PROCEDURE procedure_name
ASBEGIN-- SQL Statements here
END;

Data Modeling 🛠️

Bonus Tips

1. Use aliases for readability: SELECT column AS alias_name.
2. Learn to love and hate indexes—they can make or break performance.
3. Embrace the power of window functions for complex analyses.