标签:信息 use delete min hone 删除 span spec parent
表中出现重复数据,需要删除重复数据,只保留一条
DELETE FROM crm_participant WHERE id IN (
SELECT c.id cid FROM crm_participant c WHERE c.parentPhone IN ( SELECT a.parentPhone FROM crm_participant a GROUP BY a.parentPhone HAVING count( a.parentPhone ) > 1 ) AND c.id NOT IN ( SELECT min( b.id ) FROM crm_participant b GROUP BY b.parentPhone HAVING count( b.parentPhone ) > 1 ) ORDER BY c.parentPhone
)
错误信息:
> 1093 - You can‘t specify target table ‘crm_participant‘ for update in FROM clause
> 时间: 0.005s
问题分细:
mysql不允许对同一个表中查出来的数据作为条件,在执行跟新操作。 在一条 sql 语句中不能先查出来部分内容,再同时又对当前表作修改。
解决办法:这个是正确的sql,其实就是对上边的红色部分的查询sql进行了一层包裹。让查询出来的信息被一个 select 包裹一下,然后作为条件就可以了
DELETE FROM crm_participant WHERE id IN ( SELECT v.cid FROM ( SELECT c.id cid FROM crm_participant c WHERE c.parentPhone IN ( SELECT a.parentPhone FROM crm_participant a GROUP BY a.parentPhone HAVING count( a.parentPhone ) > 1 ) AND c.id NOT IN ( SELECT min( b.id ) FROM crm_participant b GROUP BY b.parentPhone HAVING count( b.parentPhone ) > 1 ) ORDER BY c.parentPhone ) v )
mysql修改删除You can't specify target table for update in FROM clause的问题
标签:信息 use delete min hone 删除 span spec parent
原文地址:https://www.cnblogs.com/renjianjun/p/10412703.html