[SQL] Getting the sum of several columns from two tables
- by romaintaz
I want to get the sum of several columns from 2 different tables (these tables share the same structure).
If I only consider one table, I would write this kind of query:
SELECT MONTH_REF, SUM(amount1), SUM(amount2)
FROM T_FOO
WHERE seller = XXX
GROUP BY MONTH_REF;
However, I would like to also work with the data from the table T_BAR, and then have a select query that return the following columns:
MONTH_REF
SUM(T_FOO.amount1) + SUM(T_BAR.amount1)
SUM(T_FOO.amount2) + SUM(T_BAR.amount2)
everything grouped by the value of MONTH_REF.
Note that a record for a given MONTH_REF can be found in one table but not in the other table.
In this case, I would like to get the sum of T_FOO.amount1 + 0 (or 0 + T_BAR.amount1).
How can I write my SQL query to get this information?
For information, my database is Oracle 10g.
