mysql对表中数据根据某一字段去重

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

mysql对表中数据根据某一字段去重

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