SQL字符串分组聚合(分组后的数据查询后用逗号隔开)

create table tb(id int, value varchar(10))
insert into tb values(1, 'aa')
insert into tb values(1, 'bb')
insert into tb values(2, 'aaa')
insert into tb values(2, 'bbb')
insert into tb values(2, 'ccc')
go

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