mysql 删除重复记录

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] |
+----+------------------+

来源:力扣(LeetCode)
链接:https://leetcode-cn.com/problems/delete-duplicate-emails
著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。

   DELETE t1 
   FROM
   	person t1
   	INNER JOIN person t2 
   WHERE
   	t1.id > t2.id 
   	AND t1.email = t2.email;

数据脚本

create table `person` (
	`id` int (11),
	`email` varchar (120)
); 
insert into `person` (`id`, `email`) values('1','[email protected]');
insert into `person` (`id`, `email`) values('2','[email protected]');
insert into `person` (`id`, `email`) values('3','[email protected]');

猜你喜欢

转载自www.cnblogs.com/mengjianzhou/p/12795039.html