字段查找如何去掉数据库重复记录并且只保留一条记录

最近使用开发的过程中出现了一个小问题，顺便记录一下原因和方法--字段查找

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

1、查找表中过剩的重复记录，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、删除表中过剩的重复记录，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、查找表中过剩的重复记录（多个字段）

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

4、删除表中过剩的重复记录（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、查找表中过剩的重复记录（多个字段），不包括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)

文章结束给大家分享下程序员的一些笑话语录： 姿势要丰富，经常上百度！