Skip to content
This repository was archived by the owner on Aug 17, 2024. It is now read-only.
Open
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension


Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
83 changes: 83 additions & 0 deletions 2-exercises/task.md
Original file line number Diff line number Diff line change
Expand Up @@ -35,16 +35,99 @@ 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
A = SELECT name, address FROM customers WHERE country = 'United States';
2. Retrieve all the customers in ascending name sequence
A = SELECT * FROM customers ORDER BY name ASC;
3. Retrieve all the products whose name contains the word `socks`
A = SELECT * FROM products WHERE lower(product_name) LIKE '%socks%';

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Excellent that you've made the casing match on both sides, and correctly used LIKE with wildcards % at each end

4. Retrieve all the products which cost more than 100 showing product id, name, unit price and supplier id.
A = SELECT products.id, products.product_name, product_availability.unit_price, product_availability.supp_id
FROM products
INNER JOIN product_availability
ON products.id = product_availability.prod_id;

5. Retrieve the 5 most expensive products
A =SELECT products.id, products.product_name, product_availability.unit_price
FROM products
INNER JOIN product_availability
ON products.id = product_availability.prod_id
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`
A = SELECT products.product_name, product_availability.unit_price, suppliers.supplier_name
FROM products
INNER JOIN product_availability
ON products.id = product_availability.prod_id
INNER JOIN suppliers
ON product_availability.supp_id = suppliers.id;
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`.
A = SELECT products.product_name, suppliers.supplier_name
FROM products
INNER JOIN product_availability
ON products.id = product_availability.prod_id
INNER JOIN suppliers
ON product_availability.supp_id = suppliers.id AND 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).
A = SELECT orders.id, orders.order_reference, orders.order_date, order_items.quantity * product_availability.unit_price AS total_cost

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Putting an explicit name for the calculated column as total_cost is good!

You've split the rest of the query on to one line per clause, which makes this easy to read. Sometimes it's good to split each field in the select clause into a separate line as well so I can quickly see exactly what fields are returned, without my eyes need to scan past commas.

FROM orders
INNER JOIN order_items
ON orders.id = order_items.order_id
INNER JOIN product_availability
ON order_items.product_id = product_availability.prod_id
WHERE orders.customer_id = 1;
9. Retrieve all orders, including order items, from customer named `Hope Crosby`
A = SELECT orders.id, orders.order_reference, orders.order_date, order_items.quantity * product_availability.unit_price AS total_cost
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
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`.
A = SELECT products.product_name, product_availability.unit_price, order_items.quantity
FROM orders
INNER JOIN order_items
ON orders.id = order_items.order_id
INNER JOIN products
ON order_items.product_id = products.id
INNER JOIN product_availability
ON order_items.product_id = product_availability.prod_id
WHERE orders.order_reference = 'ORD006';
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`.
A = SELECT customers.name, order_reference, order_date, products.product_name, suppliers.supplier_name,
order_items.quantity
FROM orders
INNER JOIN customers
ON orders.customer_id = customers.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
12. Retrieve the names of all customers who bought a product from a supplier based in China.
A = SELECT customers.name
FROM orders
INNER JOIN customers
ON orders.customer_id = customers.id
INNER JOIN order_items
ON orders.id = order_items.order_id
INNER JOIN suppliers
ON order_items.supplier_id = suppliers.id AND suppliers.country = 'China'
GROUP by customers.name;
13. List all orders giving customer name, order reference, order date and order total amount (quantity * unit price) in descending order of total.
A = SELECT customers.name, orders.order_reference, orders.order_date,
order_items.quantity * product_availability.unit_price AS total
FROM orders
INNER JOIN customers
ON orders.customer_id = customers.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
ORDER BY total DESC;


1 change: 1 addition & 0 deletions 3-projects/cyf-ecommerce-api/.gitignore
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
node_modules
Loading