sql sum of sums of two tables

Question

how to get a sum of two sums from two tables?

SELECT (SELECT SUM(col) FROM table1) + SELECT (SUM(col) from table2)    

doesn't work

Answer 1

You are very close. You just need parens around each subquery:

SELECT (SELECT SUM(col) FROM table1) + (SELECT SUM(col) from table2) 

If either subquery could return NULL , you might prefer:

SELECT COALESCE(t1.s, 0) + COALESCE(t2.s)
FROM (SELECT SUM(col) as s FROM table1) t1 CROSS JOIN
     (SELECT SUM(col) as s from table2) t2;

Answer 2

Due to this link , you can do that by :

SELECT T1C1 , T2C1
FROM
 ( select SUM(Col1) T1C1 FROM  T1 ) A
CROSS JOIN 
 ( select SUM(Col1) T2C1 FROM  T2 ) B

also you can visit these links:

Query SUM for two fields in two different tables

Getting the sum of several columns from two tables

SQL: How to to SUM two values from different tables

Answer 3

select coalesce(sum(x),0) from
 (
    Select sum(a) x from tab1
    Union all
    Select sum(b) from tab2
 ) Ilv