HIVE中笛卡尔积 （用A JOIN B on true 可以实现）

with aa as 
(
select 1 as num , 2 as n
union all 
select 3 as num , 4 as n
),
bb as 
(
select 4 as num , 2 as n
union all 
select 5 as num , 4 as n
)
select * 
from aa 
join bb 
on true