求sql语句
--产生基础数据
create table tb(uid int,a int,b int)
insert into tb select 1,1001,10011 union select 2,1001,10012 union select 3,1002,10021 union select 4,1002,10022
union select 5,1002,10023 union select 6,1003,10031 union select 7,1003,10032 union select 8,1003,10033
---希望结果
a b
1001 10011.10012
1002 10021.10022.10023
1003 10031.10032.10033