[LeetCode] #183 从不订购的客户

某网站包含两个表,Customers 表和 Orders 表。编写一个 SQL 查询,找出所有从不订购任何东西的客户。

Customers 表:

[LeetCode] #183 从不订购的客户

Orders 表:

[LeetCode] #183 从不订购的客户

例如给定上述表格,你的查询应返回:

[LeetCode] #183 从不订购的客户

 

左外连接

SELECT Name AS Customers FROM Customers a left JOIN Orders b ON a.Id = b.CustomerId WHERE b.Id IS NULL;

嵌套子查询

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

知识点:

总结:

 

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