标签：mamicode let expect sql HERE font 重复记录 一个 删除
要删除重复的记录，就要先查出重复的记录，这个很容易做到
select * from 表名 group by 根据哪一个字段（简称字段） having count(字段) > 1
注意：这是查出所有重复记录的第一条记录，需要保留，因此需要添加查询条件，查出所有的重复记录
select id,expect from cqssc where expect in (select expect from cqssc group by expect having count(expect)>1) and id not in(select min(id) from cqssc group by expect having count(expect)>1)
然后
delete from cqssc where id in (select id from (select id from cqssc where expect in (select expect from cqssc group by expect having count(expect)>1) and id not in (select min(id) from cqssc group by expect having count(expect)>1)) as tmpresult)
删除成功，最后再查询一下看是否还有重复记录
标签：mamicode let expect sql HERE font 重复记录 一个 删除
原文地址：https://www.cnblogs.com/wxy0126/p/11137529.html
