在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢
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