1、full outer join的使用案例？

1. 根据表A， 表B，计算表C

 

select 
  coalesce(A.dt, B.dt) as dt,
  coalesce(A.colA, 0) as colA,
  coalesce(B.colB, 0) as colB
from A
full outer join B
on a.dt = b.dt;