4,要實現以下的合併
aa bb
AB C
AB D
AB F
最後結果:
AB CDF
select 'AB' as aa,'C' as bb into testchar
select * from testchar
insert into testchar values('AB','F')
declare @a varchar(100)
declare @b varchar(5)
set @a=''
set @b=''
select @a=@a+bb,@b=aa from testchar group by aa,bb
select @b,@a