Customers Who Never Order

Desicription

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.

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+----+-------+
| Id | Name |
+----+-------+
| 1 | Joe |
| 2 | Henry |
| 3 | Sam |
| 4 | Max |
+----+-------+

Table: Orders.

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+----+------------+
| Id | CustomerId |
+----+------------+
| 1 | 3 |
| 2 | 1 |
+----+------------+

Using the above tables as example, return the following:

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+-----------+
| Customers |
+-----------+
| Henry |
| Max |
+-----------+

Solution

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SELECT Name
AS Customers
FROM Customers
WHERE Id NOT IN
(SELECT CustomerId FROM Orders)