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mysql筛选重复数据 怎样查询数据库中重复的数据?

浏览量:2272 时间:2021-03-17 21:21:05 作者:admin

怎样查询数据库中重复的数据?

1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断

select * from peoplewhere peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录

delete from people where peopleId in (select peopleId from people group by peopleId having count (peopleId) > 1)and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>1)

3、查找表中多余的重复记录(多个字段)

select * from vitae awhere (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having

如何查找数据库中的重复数据?

下面以 sqlserver数据库为例进行说明。 select * from TableA where b in (select b from TableA group by b having count(b) > 1) 这样就列举出了b字段所有的重复数据,可以根据对应的行号,取得位于第几行。 如果要查询a字段或者c字段重复数据,可以相应的把上面的b字段替换成a字段或c字段即可。 举例: 1、创建表student 2、查询语句: select * from student where name in (select name from student group by name having count(name ) > 1) 这样就查出名字重复列,以及行号id。

mysql筛选重复数据 查找数据重复的数据 mysql查询重复数据数量

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