LeetCode 183. Customers Who Never Order

分析

难度 易

来源

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

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       |

+-----------+

解答

Runtime: 220 ms, faster than 94.79% of MySQL online submissions for Customers Who Never Order.

# Write your MySQL query statement below

select Name as Customers from Customers where Id not in (select CustomerId from Orders);