如何去掉数据库重复记录并且只保留一条记录_动视

如何去掉数据库重复记录并且只保留一条记录

2020-11-09 16:03:51 责编:小采

在n条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复并保留一条呢？方法如下： 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 hav

在n条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复并保留一条呢？

方法如下：

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 people
where 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 a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录

delete from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录

select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

下载本文

显示全文

全部频道