Added Customers Who Never Order

Author: ignacio-chiazzo

LeetcodeProblems/Databases/Customers_Who_Never_Order.sql

@@ -0,0 +1,37 @@
+/*
+Customers Who Never Order
+
+SQL Schema
+Suppose that a website contains two tables, the Customers table and the Orders table. Write a SQL query to find all customers who never order anything.
+
+Table: Customers.
+
++----+-------+
+| Id | Name  |
++----+-------+
+| 1  | Joe   |
+| 2  | Henry |
+| 3  | Sam   |
+| 4  | Max   |
++----+-------+
+Table: Orders.
+
++----+------------+
+| Id | CustomerId |
++----+------------+
+| 1  | 3          |
+| 2  | 1          |
++----+------------+
+Using the above tables as example, return the following:
+
++-----------+
+| Customers |
++-----------+
+| Henry     |
+| Max       |
++-----------+
+*/
+
+SELECT Customers.Name as Customers
+FROM Customers LEFT JOIN Orders ON customers.id = Orders.CustomerId
+WHERE Orders.id IS NULL 

README.md

@@ -84,7 +84,7 @@ To run a specific problem in your console, go to the file test, add the call to
 | [Combine Two Tables](/LeetcodeProblems/Databases/Combine_Two_Tables.sql) | Easy   | https://leetcode.com/problems/combine-two-tables |
 | [Second Highest Salary](/LeetcodeProblems/Databases/Second_highest_salary.sql)| Easy   | https://leetcode.com/problems/second-highest-salary |
 | [Nth Highest Salary](/LeetcodeProblems/Databases/nth_Highest_Salary.sql) | Medium | https://leetcode.com/problems/nth-highest-salary |
-
+| [Customers Who Never Order](/LeetcodeProblems/Databases/Customers_Who_Never_Order.sql)| Easy |  https://leetcode.com/problems/customers-who-never-order |
 
 ### UtilsClasses