这样一个 query ， explain plan for
select
*
from t1
where n2 = (
select
max(t2.n2)
from t2
where t2.n1 = t1.n1
and t2.v1 ='xxx'
)
;
在 subquery unnest 后 ， 有两个 选择， 1：T2 先 hash group by 再 join T ...
↧