用SQL语句,删除掉重复项只保留一条
时间：2021-07-01 10:21:17
帮助过：5人阅读
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 peopleName
in (
select peopleName
from people
group by peopleName
having count(peopleName)
> 1)
and peopleId
not in (
select min(peopleId)
from people
group by peopleName
having count(peopleName)
>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)
6.消除一个字段的左边的第一位：
update tableName
set [Title]=Right(
[Title],(
len(
[Title])
-1))
where Title
like ‘村%‘
7.消除一个字段的右边的第一位：
update tableName
set [Title]=left(
[Title],(
len(
[Title])
-1))
where Title
like ‘%村‘
8.假删除表中多余的重复记录（多个字段），不包含rowid最小的记录
update vitae
set ispass
=-1
where peopleId
in (
select peopleId
from vitae
group by peopleId
用SQL语句,删除掉重复项只保留一条
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