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使用sql查询数据库中表的重复的数据的5种方法

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 (
-- 所有peopleId数量大于1的peopleId 
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

-- 查询重复数据,并且剔除不符合条件的数据
select * from vitae a
where (a.peopleId,a.seq) in   (
-- 所有符合条件的重复数据
select peopleId,seq from vitae group by peopleId,seq having count(*) > 1
)
and rowid not in (
--重复数据中最小的rowid
select min(rowid) from vitae group by peopleId,seq having count(*)>1
)
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  • 评论 1
陈开华 多么熟悉的sql语句。
2016/11/22 16:28:15 回复

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