task: 1045

Author: Ivanbyone

README.md

@@ -46,6 +46,7 @@ Have a good contributing!
 2. [Medium](./leetcode/medium/)
     - [176. Second Highest Salary](./leetcode/medium/176.%20Second%20Highest%20Salary.sql)
     - [184. Department Highest Salary](./leetcode/medium/184.%20Department%20Highest%20Salary.sql)
+    - [1045. Customers Who Bought All Products](./leetcode/medium/1045.%20Customers%20Who%20Bought%20All%20Products.sql)
     - [1070. Product Sales Analysis III](./leetcode/medium/1070.%20Product%20Sales%20Analysis%203.sql)
     - [1158. Market Analysis 1](./leetcode/medium/1158.%20Market%20Analysis%201.sql)
 

leetcode/medium/1045. Customers Who Bought All Products.sql

@@ -0,0 +1,43 @@
+/*
+Question 1045. Customers Who Bought All Products
+Link: https://leetcode.com/problems/customers-who-bought-all-products/description/
+
+Table: Customer
+
++-------------+---------+
+| Column Name | Type    |
++-------------+---------+
+| customer_id | int     |
+| product_key | int     |
++-------------+---------+
+This table may contain duplicates rows. 
+customer_id is not NULL.
+product_key is a foreign key (reference column) to Product table.
+ 
+
+Table: Product
+
++-------------+---------+
+| Column Name | Type    |
++-------------+---------+
+| product_key | int     |
++-------------+---------+
+product_key is the primary key (column with unique values) for this table.
+ 
+
+Write a solution to report the customer ids from the Customer table that bought all the products in the Product table.
+
+Return the result table in any order.
+*/
+
+WITH Customer_products AS (
+    SELECT customer_id, COUNT(DISTINCT product_key) as c
+    FROM Customer
+    GROUP BY customer_id
+)
+SELECT customer_id
+FROM Customer_products
+WHERE c = (
+    SELECT COUNT(1)
+    FROM Product
+)