Performing a query on a result from another query?

Question

I have a the query:

SELECT availables.bookdate AS Date, DATEDIFF(now(),availables.updated_at) as Age
FROM availables
INNER JOIN rooms
ON availables.room_id=r         


        

Answer 1

You just wrap your query in another one:

SELECT COUNT(*), SUM(Age)
FROM (
    SELECT availables.bookdate AS Count, DATEDIFF(now(),availables.updated_at) as Age
    FROM availables
    INNER JOIN rooms
    ON availables.room_id=rooms.id
    WHERE availables.bookdate BETWEEN '2009-06-25' AND date_add('2009-06-25', INTERVAL 4 DAY) AND rooms.hostel_id = 5094
    GROUP BY availables.bookdate
) AS tmp;