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:

±—±------+

| Id | Name |

±—±------+

| 1 | Joe |

| 2 | Henry |

| 3 | Sam |

| 4 | Max |

±—±------+

Orders 表:

±—±-----------+

| Id | CustomerId |

±—±-----------+

| 1 | 3 |

| 2 | 1 |

±—±-----------+

例如给定上述表格,你的查询应返回:

±----------+

| Customers |

±----------+

| Henry |

| Max |

±----------+

1.子查询 + not in

select Name  as Customers  from Customers where id not in (select distinct(CustomerId) from orders);