DB2如何对来自两个不同表的两个列求和

Question

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

What is the best way if the objective is to have sum(totalA + totalB) ?

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