【MySQL】【leetcode】 Customers Who Never Order解题报告

题目

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 |

+———–+

题目来源：https://leetcode.com/problems/customers-who-never-order/

代码

找出没有买东西的那些人的名字。

# Write your MySQL query statement below
select Name from
Customers where Id not in(
select t_c.Id from Customers as t_c, Orders as t_o
where t_c.Id = t_o.CustomerId
);