delete [dtzrc_888].[dbo].[Company2]
where [CompanyID] not in (
select max([CompanyID]) from [dtzrc_888].[dbo].[Company2] Where Own = 1
group by (TheftCompanyID + TheftWebID))我只想删除 Own字段是1 的重复记录,所以写了 Where Own = 1 为什么执行以后 Own = 1 的数据也会被删除,哪里写错了吗?
where [CompanyID] not in (
select max([CompanyID]) from [dtzrc_888].[dbo].[Company2] Where Own = 1
group by (TheftCompanyID + TheftWebID))我只想删除 Own字段是1 的重复记录,所以写了 Where Own = 1 为什么执行以后 Own = 1 的数据也会被删除,哪里写错了吗?
取的own=1 最大的不删除。不是最大的就删除了哦!
WHERE EXISTS(SELECT 1 FROM TB WHERE
TheftCompanyID +TheftWebID=T.TheftCompanyID + T.TheftWebID AND
CompanyID>T.CompanyID AND Own = 1
) AND Own = 1
where [CompanyID] not in (
select max([CompanyID]) from [dtzrc_888].[dbo].[Company2] Where Own = 1
group by (TheftCompanyID + TheftWebID))
and Own <> 1
删除重复记录有大小关系时,保留大或小其中一个记录
--> --> (Roy)生成測試數據if not object_id('Tempdb..#T') is null
drop table #T
Go
Create table #T([ID] int,[Name] nvarchar(1),[Memo] nvarchar(2))
Insert #T
select 1,N'A',N'A1' union all
select 2,N'A',N'A2' union all
select 3,N'A',N'A3' union all
select 4,N'B',N'B1' union all
select 5,N'B',N'B2'
Go--I、Name相同ID最小的记录(推荐用1,2,3),保留最小一条
方法1:
delete a from #T a where exists(select 1 from #T where Name=a.Name and ID<a.ID)方法2:
delete a from #T a left join (select min(ID)ID,Name from #T group by Name) b on a.Name=b.Name and a.ID=b.ID where b.Id is null方法3:
delete a from #T a where ID not in (select min(ID) from #T where Name=a.Name)方法4(注:ID为唯一时可用):
delete a from #T a where ID not in(select min(ID)from #T group by Name)方法5:
delete a from #T a where (select count(1) from #T where Name=a.Name and ID<a.ID)>0方法6:
delete a from #T a where ID<>(select top 1 ID from #T where Name=a.name order by ID)方法7:
delete a from #T a where ID>any(select ID from #T where Name=a.Name)select * from #T生成结果:
/*
ID Name Memo
----------- ---- ----
1 A A1
4 B B1(2 行受影响)
*/