How do I add two count(*) results together on two different tables?
I have two tables: Toys and Games.
+--------------------+------------------+
| Field | Type |
+--------------------+------------------+
| toy_id | int(10) unsigned |
| little_kid_id | int(10) unsigned |
+--------------------+------------------+
+--------------------+------------------+
| Field | Type |
+--------------------+------------------+
| game_id | int(10) unsigned |
| little_kid1 | int(10) unsigned |
| little_kid2 | int(10) unsigned |
| little_kid3 | int(10) unsigned |
+--------------------+------------------+
A little kid can have multiple toys. A little kid can be participating in multiple games at once.
I want a query that will give me the total number of toys + games that a little_kid is involved with.
Basically, I want the sum of these two queries:
SELECT COUNT(*) FROM Toys WHERE little_kid_id = 900; SELECT COUNT(*) from Games WHERE little_kid1 = 900 OR little_kid2 = 900 OR little_kid3 = 900;
Is it possible to get this in a single SQL query? Obviously, I can sum them programmatically, but that's less desirable.
(I realize that the contrived example makes the schema look ineffecient. Let's assume that we can't change the schema.)
Solution 1:
Wrap them up and use subqueries:
SELECT
(SELECT COUNT(*) FROM Toys WHERE little_kid_id = 900)+
(SELECT COUNT(*) from Games WHERE little_kid1 = 900
OR little_kid2 = 900
OR little_kid3 = 900)
AS SumCount
Voila!
Solution 2:
SELECT
((SELECT COUNT(*) FROM Toys WHERE little_kid_id = 900)+
(SELECT COUNT(*) from Games WHERE little_kid1 = 900
OR little_kid2 = 900
OR little_kid3 = 900))
AS Sum FROM DUAL;
Selecting from the DUAL Table
Solution 3:
SELECT COUNT(1) FROM
(
SELECT 1 FROM Toys WHERE little_kid_id = 900
UNION
SELECT 1 FROM Games WHERE little_kid1 = 900
OR little_kid2 = 900
OR little_kid3 = 900
)