Shopify Data Engineer Intern Assessment - Alpin Aydiner

sql/task1.sql

@@ -1,14 +1,37 @@
 -- Problem 1: Retrieve all products in the Sports category
 -- Write an SQL query to retrieve all products in a specific category.
+-- Utilize category ID to select desired products listed within the category
+-- Category ID may be changed to better suit search parameters
+SELECT *
+FROM Products
+WHERE Products.category_id = 8;
 
 -- Problem 2: Retrieve the total number of orders for each user
 -- Write an SQL query to retrieve the total number of orders for each user.
 -- The result should include the user ID, username, and the total number of orders.
 
+SELECT Users.user_id, Users.username, COUNT(Order.order_id) AS total_orders
+FROM Users
+LEFT JOIN Orders ON Users.user_id = Orders.user_id
+GROUP BY Users.user_id, Users.username;
+
+
 -- Problem 3: Retrieve the average rating for each product
 -- Write an SQL query to retrieve the average rating for each product.
 -- The result should include the product ID, product name, and the average rating.
 
+SELECT Products.product_id, Products.product_name, AVG(Reviews.rating) AS average_rating
+FROM Products
+LEFT JOIN Reviews ON Products.product_id = Reviews.product_id
+GROUP BY Products.product_id, Products.product_name;
+
 -- Problem 4: Retrieve the top 5 users with the highest total amount spent on orders
 -- Write an SQL query to retrieve the top 5 users with the highest total amount spent on orders.
 -- The result should include the user ID, username, and the total amount spent.
+
+SELECT Users.user_id, Users.username, SUM(Orders.total_amount) AS total_amount_spent
+FROM Users
+JOIN Orders ON Users.user_id = Orders.user_id
+GROUP BY Users.user_id, Users.username
+ORDER BY total_amount_spent DESC
+LIMIT 5;

sql/task2.sql

@@ -3,17 +3,40 @@
 -- The result should include the product ID, product name, and the average rating.
 -- Hint: You may need to use subqueries or common table expressions (CTEs) to solve this problem.
 
+SELECT Products.product_id, Products.product_name, Reviews.rating AS average_rating
+FROM Products
+LEFT JOIN Reviews ON Reviews.product_id = Products.product_id
+WHERE Reviews.rating = (SELECT MAX(average_rating) 
+FROM (SELECT Products.product_id, Products.product_name, AVG(Reviews.rating) AS average_rating
+FROM Products
+LEFT JOIN Reviews ON Products.product_id = Reviews.product_id
+GROUP BY Products.product_id, Products.product_name));
+
 -- Problem 6: Retrieve the users who have made at least one order in each category
 -- Write an SQL query to retrieve the users who have made at least one order in each category.
 -- The result should include the user ID and username.
 -- Hint: You may need to use subqueries or joins to solve this problem.
 
+SELECT Users.user_id, Users.username
+FROM Users
+JOIN Orders ON Users.user_id = Orders.order_id
+JOIN Order_Items ON Orders.order_id = Order_Items.order_id
+JOIN Products ON Order_Items.product_id = Products.product_id
+JOIN Categories ON Products.category_id = Categories.category_id
+GROUP BY Users.user_id
+HAVING COUNT(DISTINCT Categories.category_id) = (SELECT COUNT(category_id) FROM Categories);
+
 -- Problem 7: Retrieve the products that have not received any reviews
 -- Write an SQL query to retrieve the products that have not received any reviews.
 -- The result should include the product ID and product name.
 -- Hint: You may need to use subqueries or left joins to solve this problem.
+SELECT Products.product_id, Products.product_name
+FROM Products
+LEFT JOIN Reviews ON Products.product_id = Reviews.product_id
+WHERE Reviews.review_id IS NULL;
 
 -- Problem 8: Retrieve the users who have made consecutive orders on consecutive days
 -- Write an SQL query to retrieve the users who have made consecutive orders on consecutive days.
 -- The result should include the user ID and username.
--- Hint: You may need to use subqueries or window functions to solve this problem.
+-- Hint: You may need to use subqueries or window functions to solve this problem.
+

sql/task3.sql

@@ -3,15 +3,37 @@
 -- The result should include the category ID, category name, and the total sales amount.
 -- Hint: You may need to use subqueries, joins, and aggregate functions to solve this problem.
 
+SELECT Categories.category_id, Categories.category_name, SUM(Orders.total_amount) AS total_sales
+FROM Categories
+JOIN Products ON Categories.category_id = Products.category_id
+JOIN Order_Items ON Products.product_id = Order_Items.product_id
+JOIN Orders ON Order_Items.order_id = Orders.order_id
+GROUP BY Categories.category_id, Categories.category_name
+ORDER BY total_sales DESC
+LIMIT 3
+
 -- Problem 10: Retrieve the users who have placed orders for all products in the Toys & Games
 -- Write an SQL query to retrieve the users who have placed orders for all products in the Toys & Games
 -- The result should include the user ID and username.
 -- Hint: You may need to use subqueries, joins, and aggregate functions to solve this problem.
 
+SELECT Users.user_id, Users.username
+FROM Users
+JOIN Orders ON Users.user_id = Orders.user_id
+JOIN Order_Items ON Orders.order_id = Order_Items.order_id
+JOIN Products ON Order_Items.product_id = Products.product_id
+JOIN Categories ON Products.category_id = Categories.category_id
+GROUP BY Users.user_id, Users.username
+HAVING COUNT(DISTINCT Products.product_id) = (SELECT COUNT(DISTINCT product_id) FROM Products WHERE category_id = 5);
+
 -- Problem 11: Retrieve the products that have the highest price within each category
 -- Write an SQL query to retrieve the products that have the highest price within each category.
 -- The result should include the product ID, product name, category ID, and price.
 -- Hint: You may need to use subqueries, joins, and window functions to solve this problem.
+SELECT product_id, product_name, category_id, price
+FROM (SELECT *, ROW_NUMBER() OVER (PARTITION BY category_id ORDER BY price DESC) AS price_rows
+FROM Products) AS Ranked_Prices
+WHERE price_rows = 1;
 
 -- Problem 12: Retrieve the users who have placed orders on consecutive days for at least 3 days
 -- Write an SQL query to retrieve the users who have placed orders on consecutive days for at least 3 days.