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LeetCode: 196. 删除重复的电子邮箱

1、题目描述

编写一个 SQL 查询,来删除 Person 表中所有重复的电子邮箱,重复的邮箱里只保留 Id 最小 的那个。

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | [email protected] |
| 2  | [email protected]  |
| 3  | [email protected] |
+----+------------------+
Id 是这个表的主键。

例如,在运行你的查询语句之后,上面的 Person 表应返回以下几行:

+----+------------------+
| Id | Email            |
+----+------------------+
| 1  | [email protected] |
| 2  | [email protected]  |
+----+------------------+

2、解题思路

# Write your MySQL query statement below
delete p1 from Person p1, Person p2 where p1.Email = p2.Email and p1.Id > p2.Id
# Write your MySQL query statement below
delete from Person where Id not in (select Id from (select min(Id) Id from Person group by Email) p)