183.Customers Who Never Order
难度:Easy
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       |
+-----------+
需要注意Orders表中的去重，
# Write your MySQL query statement below
SELECT Name as Customers from Customers WHERE Id NOT IN (SELECT DISTINCT CustomerId from Orders)

182.Duplicate Emails

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Last updated 2 years ago