用CTE处理表重复数据的更新和删除

Posted 2021-05-16 中国风

--> --> (Roy)生成測試數據
set nocount on ;
if not object_id('Tempdb..#T') is null
    drop table #T
Go
Create table #T([Num] int,[Name] nvarchar(1))
Insert #T
select 1,N'A' union all
select 1,N'A' union all
select 2,N'B' union all
select 2,N'B'

go

--Delete
;with CTE as
(select row=row_number()over(partition by [Num],[Name] order by (select 1)),[Num],[Name] from #T)
delete CTE where 	row>1

select * from #T
/*
Num         Name
----------- ----
1           A
2           B
*/

--insert
;with CTE as
(select [Num],[Name] from #T)
insert CTE
select * from CTE

select * from #T
/*
Num         Name
----------- ----
1           A
1           A
2           B
2           B
*/

--update
;with CTE as
(select row=row_number()over(partition by [Num] order by (select 1)),[Num],[Name] from #T)
update CTE
set [Num]=CTE.row

select * from #T
/*
Num         Name
----------- ----
1           A
2           A
1           B
2           B
*/

 

处理重复数据查询和其它方法

http://topic.csdn.net/u/20080626/00/43d0d10c-28f1-418d-a05b-663880da278a.html