DB2 두 개의 다른 테이블에서 두 개의 열을 더하는 방법

Question

Select sum(amt) as totalA from tableA where id>10; 
Select sum(amount) as totalB from tableB where people = 'JOSH'; 

sum(totalA + totalB)을 갖는 것이 가장 좋은 방법은 무엇입니까?

Answer 1

select sum(total) from 
(
    select sum(amt) as total from tableA where id>10 
    union all 
    select sum(amount) from tableB where people = 'JOSH' 
) as q