SQL去除重复记录
if not object_id('Tempdb..#T') is null
drop table #T
GoCreate 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