SQL stuff函数拼接字符串

有时，我们需要将表数据根据分组，统一在一个字段中，请看实例：

1、将测试数据插入临时表：

create table #tb(id int, value varchar(10))  
insert into #tb values(1, 'a')  
insert into #tb values(1, 'b')  
insert into #tb values(2, 'aa')  
insert into #tb values(2, 'bb')  
insert into #tb values(2, 'cc')  
insert into #tb values(3, 'aaa') 
insert into #tb values(3, 'bbb') 
insert into #tb values(3, 'ccc') 
insert into #tb values(3, 'ddd') 
insert into #tb values(4, 'aaaa') 
insert into #tb values(4, 'bbbb') 
insert into #tb values(4, 'cccc') 
insert into #tb values(4, 'dddd') 
go  

select一下：select * from #tb

要达到下面的效果：

语句如下：

select id, [value] = stuff((select ',' + [value] from #tb t where id = #tb.id for xml path('')) , 1 , 1 , '')  
from #tb  
group by id