select a02 from a where a01 in (select b01 from b where b02 = '你自己的值' )
select a02 from a where exists (select 1 from b where a.a01=b.b01 and b02 = '你自己的值' )
------解决方案-------------------- 哪个1哪个多?
这个?
select a02
from a,b
where a.a01 = b.b01 and b.b02 = '**'