Mysql删除重复数据保留最小的id

时间:2022-05-19 06:24:03

在网上查找删除重复数据保留id最小的数据,方法如下:

 DELETE
FROM
people
WHERE
peopleName IN (
SELECT
peopleName
FROM
people
GROUP BY
peopleName
HAVING
count(peopleName) >
)
AND peopleId NOT IN (
SELECT
min(peopleId)
FROM
people
GROUP BY
peopleName
HAVING
count(peopleName) >
)

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)>)

[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:

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

 delete from tb where id=xx

是个笨方法,暂时先解决问题吧。