NW5_Leeds-Meron_Gebremichael-SQL-Coursework-Week2

2-exercises/task.md

@@ -35,16 +35,80 @@ Open the file `cyf_ecommerce.sql` in VSCode and examine the SQL code. Take a pie
 Once you understand the database that you are going to work with, solve the following challenge by writing SQL queries using everything you learned about SQL:
 
 1. Retrieve all the customers' names and addresses who live in the United States
+
+ => select name from customers where country = 'United Kingdom';
+
 2. Retrieve all the customers in ascending name sequence
+
+=> SELECT name FROM customers ORDER BY name ASC;
+
 3. Retrieve all the products whose name contains the word `socks`
+
+=> SELECT \* from products WHERE product_name LIKE '%socks%';
+
 4. Retrieve all the products which cost more than 100 showing product id, name, unit price and supplier id.
+
+=> SELECT products.\*, product_availability.unit_price, product_availability.supp_id
+ FROM products, product_availability
+ WHERE product_availability.unit_price > 100;
+
 5. Retrieve the 5 most expensive products
+
+=> SELECT \* FROM products, product_availability ORDER BY product_availability.unit_price DESC
+ LIMIT 5;
+
 6. Retrieve all the products with their corresponding suppliers. The result should only contain the columns `product_name`, `unit_price` and `supplier_name`
+
+=> SELECT products.product_name, product_availability.unit_price, suppliers.supplier_name
+ FROM products, product_availability, suppliers;
+
 7. Retrieve all the products sold by suppliers based in the United Kingdom. The result should only contain the columns `product_name` and `supplier_name`.
+
+=> SELECT products.product_name, suppliers.supplier_name
+ FROM products, suppliers
+ WHERE suppliers.country = "United Kingdom";
+
 8. Retrieve all orders, including order items, from customer ID `1`. Include order id, reference, date and total cost (calculated as quantity * unit price).
+
+=> SELECT orders.id, orders.order_reference , orders.order_date , (order_items.quantity \* product_availability.unit_price) as total_cost
+ FROM orders
+ INNER JOIN order_items ON order_items.order_id = orders.id
+ INNER JOIN product_availability ON product_availability.prod_id = order_items.product_id
+ WHERE orders.customer_id = 1;
+
 9. Retrieve all orders, including order items, from customer named `Hope Crosby`
+
+=> SELECT o.id, o.order_reference, o.order_date,customers.name FROM orders AS o INNER JOIN customers ON customers.id = o.customer_id INNER JOIN order_items AS oi ON oi.id = oi.order_id WHERE customers.name ='Hope Crosby';
+
 10. Retrieve all the products in the order `ORD006`. The result should only contain the columns `product_name`, `unit_price` and `quantity`.
+
+=> SELECT products.product_name, product_availability.unit_price, order_items.quantity
+FROM orders
+INNER JOIN order_items ON order_items.order_id=orders.id AND order_reference='ORD006'
+INNER JOIN products ON order_items.product_id=products.id
+INNER JOIN product_availability ON order_items.supplier_id=product_availability.supp_id;
+
 11. Retrieve all the products with their supplier for all orders of all customers. The result should only contain the columns `name` (from customer), `order_reference`, `order_date`, `product_name`, `supplier_name` and `quantity`.
+
+=> SELECT customers.name, orders.order_reference, orders.order_date, products.product_name, suppliers.supplier_name, order_items.quantity
+
 12. Retrieve the names of all customers who bought a product from a supplier based in China.
+
+=> SELECT DISTINCT customers.name
+FROM customers
+INNER JOIN orders ON customers.id = orders.customer_id
+INNER JOIN order_items ON orders.id = order_items.order_id
+INNER JOIN products ON order_items.product_id = products.id
+INNER JOIN suppliers ON order_items.supplier_id = suppliers.id
+WHERE suppliers.country = 'China';
+
 13. List all orders giving customer name, order reference, order date and order total amount (quantity * unit price) in descending order of total.
 
+=> SELECT customers.name, orders.order_reference, orders.order_date, SUM(order_items.quantity \* product_availability.unit_price) AS total
+FROM customers
+INNER JOIN orders ON customers.id = orders.customer_id
+INNER JOIN order_items ON orders.id = order_items.order_id
+INNER JOIN product_availability ON order_items.product_id = product_availability.prod_id AND order_items.supplier_id = product_availability.supp_id
+GROUP BY customers.name, orders.order_reference, orders.order_date
+ORDER BY total DESC;
+

3-projects/task.md

@@ -7,6 +7,7 @@ Add all your `javascript` files in this folder and create a pull request to subm
 ## Task
 
 - Create a new NodeJS application called `cyf-ecommerce-api`
+
 - Add Express and node-postgres and make sure you can start the server with `node server.js`
 - Add a new GET endpoint `/customers` to return all the customers from the database
 - Add a new GET endpoint `/suppliers` to return all the suppliers from the database