在网上查找删除重复数据保留id最小的数据,方法如下:
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DELETE FROM people WHERE peopleName IN ( SELECT peopleName FROM people GROUP BY peopleName HAVING count (peopleName) > 1 ) AND peopleId NOT IN ( SELECT min (peopleId) FROM people GROUP BY peopleName HAVING count (peopleName) > 1 ) |
自己使用的时候显示报错:
delete from tb where id in (SELECT max(id) from tb GROUP BY user HAVING count(user)>1)
[Err] 1093 - You can't specify target table ‘XXX' for update in FROM clause
暂时不知道是什么原因导致的。
然后想办法分布操作,首先筛选出有重复user的数据,然后用max()选出其中较大的那一行:
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SELECT max (id) from tb GROUP BY user HAVING count ( user )>1 |
然后再根据得到的max(id)逐条删除多余的数据
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delete from tb where id=xx |
是个笨方法,暂时先解决问题吧。
总结
以上所述是小编给大家介绍的Mysql删除重复数据保留最小的id 的解决方法,希望对大家有所帮助,如果大家有任何疑问欢迎给我留言,小编会及时回复大家的!
原文链接:http://www.cnblogs.com/mengms/archive/2017/10/07/7634048.html