小编给大家分享一下MySql中数据去重的示例分析,相信大部分人都还不怎么了解,因此分享这篇文章给大家参考一下,希望大家阅读完这篇文章后大有收获,下面让我们一起去了解一下吧!
1.查出重复数据
SELECT member_email FROM group_member GROUP BY member_email HAVING COUNT(member_email) > 1
2.去除重复数据
delete from group_member
where member_email in
(
select TEMP.member_email from (
SELECT member_email FROM group_member GROUP BY member_email HAVING COUNT(member_email) > 1
) as temp
)
and id not in
(select temp2.id from(
select min(id) as id from group_member GROUP BY member_email HAVING COUNT(member_email) > 1
)as temp2
);
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