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) > 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：
1 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：
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
1 delete from tb where id=xx
