database - Join two sql queries

Question

I have two SQL queries, where the first one is:

select Activity, SUM(Amount) as "Total Amount 2009"
from Activities, Incomes
where Activities.UnitName = ? AND
      Incomes.ActivityId = Activities.ActivityID
GROUP BY Activity
ORDER BY Activity;

and the second one is:

select Activity, SUM(Amount) as "Total Amount 2008"
from Activities, Incomes2008
where Activities.UnitName = ? AND
      Incomes2008.ActivityId = Activities.ActivityID
GROUP BY Activity
ORDER BY Activity;

(Dont mind the '?', they represent a parameter in birt). What i want to achieve is the following: I want an SQL query that returns the same as the first query, but with an additional (third) column which looks exactly like "Total Amount 2008" (from the 2nd query).

Answer 1

Some DBMSs support the FROM (SELECT ...) AS alias_name syntax.

Think of your two original queries as temporary tables. You can query them like so:

SELECT t1.Activity, t1."Total Amount 2009", t2."Total Amount 2008"
FROM (query1) as t1, (query2) as t2
WHERE t1.Activity = t2.Activity