MySQL COUNT(*) GROUP BY HAVING COUNT=?

Question

This my Query

SELECT COUNT(*) as total, toys, date FROM T1
 WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
UNION
SELECT COUNT(*) as total, toys, date FROM T2
 WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
UNION
SELECT COUNT(*) as total, toys, date FROM T3
 WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
GROUP BY RoomType
HAVING COUNT( total ) = 4

Output result

count   Toys            date
3   Bibi        2012-06-26
4   Baba            2012-06-26

How can i get MYSQL to show results only for count=4

Answer 1

SELECT * FROM (
    SELECT COUNT(*) as total, toys, date FROM T1
     WHERE (date >= '2012-06-26' AND date < '2012-06-30') AND (Avail > '0')
     GROUP BY RoomType
    UNION
    SELECT COUNT(*) as total, toys, date FROM T2
     WHERE (date >= '2012-06-26' AND date < '2012-06-30') AND (Avail > '0')
     GROUP BY RoomType
    UNION
    SELECT COUNT(*) as total, toys, date FROM T3
     WHERE (date >= '2012-06-26'AND date < '2012-06-30') AND (Avail > '0')
    GROUP BY RoomType) AS src
WHERE total = 4;

Please, note, that for proper data groupping you must have all columns either in the GROUP BY clause or as arguments to the aggregate functions. It is MySQL feature to allow you to avoid this restriction, but it might lead you to the unexpected results.