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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.
1 # Write your MySQL query statement below
2 
3 select Name as Customers from Customers where Id not in (select CustomerId from Orders);

 

posted on 2018-11-18 11:02  flowingfog  阅读(67)  评论(0编辑  收藏