关于UPDATE的一个用法

CREATE TABLE [dbo].[tb] (


[name] [varchar] (100) COLLATE Chinese_PRC_CI_AS NULL


) ON [PRIMARY]


GO




insert into tb


Select ('a')


union


select ('b')


union


select ('b')


union


select ('a')


union


select ('a')


union


select ('b')




declare @i int


declare @y varchar(100)




select identity(int,1,1) id,0 as uid ,name into # from tb order by name




Update # Set uid = Case When name = @y then @i else 1 end,


@i = case When name = @y Then @i + 1 else 1 end, @y = name




id uid name


----------- ----------- --------------------


1 1 a


2 2 a


3 3 a


4 1 b


5 2 b


6 3 b