时间：2021-07-01 10:21:17 帮助过：26人阅读
where tel in (select min(dpxx_id) from zqzrdp group by tel having count(tel)>1);
执行，报错 
异常意为：你不能指定目标表的更新在FROM子句。傻了，MySQL 这样写，不行，让人郁闷。
难倒只能分步操作，蛋疼
以下是网友写的，同样是坑爹的代码，我机器上运行不了。
1. 查询需要删除的记录，会保留一条记录。
| 代码如下 | |
| select a.id,a.subject,a.RECEIVER from test1 a left join (select c.subject,c.RECEIVER ,max(c.id) as bid from test1 c where status=0 GROUP BY RECEIVER,SUBJECT having count(1) >1) b on a.id< b.bid where a.subject=b.subject and a.RECEIVER = b.RECEIVER and a.id < b.bid | |
2. 删除重复记录，只保留一条记录。注意，subject,RECEIVER 要索引，否则会很慢的。
| 代码如下 | |
| delete a from test1 a, (select c.subject,c.RECEIVER ,max(c.id) as bid from test1 c where status=0 GROUP BY RECEIVER,SUBJECT having count(1) >1) b where a.subject=b.subject and a.RECEIVER = b.RECEIVER and a.id < b.bid; | |
3. 查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断
| 代码如下 | |
| select * from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) | |
4. 删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录
| 代码如下 | |
| delete from people where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1) and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1) | |
5.删除表中多余的重复记录（多个字段），只留有rowid最小的记录