with test_sl as (
select 0 as sl from dual --语句已经简化，实际是很长的一段语句；
),
test_aa as (
select 'aa' as a from dual --语句已经简化，实际是很长的一段语句；
),
test_bb as (
select 'bb' as a from dual --语句已经简化，实际是很长的一段语句；
)
select test_aa.* from test_aa ,(select sl from test_sl where sl>0)
union all
select test_bb.* from test_bb ,(select sl from test_sl where sl=0)
