create table #1

(

   a int,

   b  varchar(10)

)

insert into #1 values(1,'aa')

insert into #1

select 1,'1a' union all

select 2,'1b' union all

select 3,'1c'

go

select * from #1

declare @str varchar(8000)

declare @bb varchar(20)

select @str= isnull(@str+',','')+b

from #1

select @str