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剔除表中相同的记录

2012-12-14 
删除表中相同的记录1、查找表中的重复记录,重复记录是根据单个字段(id)来判断select * from peoplewhere id

删除表中相同的记录

1、查找表中的重复记录,重复记录是根据单个字段(id)来判断
select * from people
where id in (select id from people group by peopleId having count(id) > 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)
(红色为可选参数,当如果需要都删除的时候则,可不加该条语句,如果只留其一,则可考虑。)

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同样也可以通过多个字段来判断重复性。

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)

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