如何查找字段中用逗号隔开的id的列表

[无爱大叔]

a表基础数据表
b表业务表，b表里字段aid存放了a表的id，形如：1,2,3

如何查出b表里某条记录对应a表1,2,3这3条记录的列表；错误的sql如下：
select a.* from a where aid in (select b.aid from b where b.id='AC2015021')

[zbdzjx]

with table1 as
(
select '1' id, 'a' col1 from dual union all
select '2' id, 'b' col1 from dual union all
select '3' id, 'c' col1 from dual union all
select '4' id, 'd' col1 from dual union all
select '5' id, 'e' col1 from dual
)
, table2 as
(
select '1,2,3' id_all from dual
)
select a.* from table1 a, table2 b where ',' || b.id_all || ',' like '%,' || a.id || ',%'