Question

I am using a MySQL database and I have a big mysql_query that works completely fine except for this one line.

SELECT game_id, 
COALESCE(
SUM(CASE WHEN game_score = 1 THEN 1 ELSE 0 END) 
- 
SUM(CASE WHEN game_score = 0 THEN 1 ELSE 0 END), 0) AS score 
FROM .... 
WHERE .... 
GROUP BY ....

This line returns me almost all of the numbers that I want, yet they are the same numbers as when I wasn’t using the COALESCE function.
I would like this statement to return me 0 when there is a game_id that has an emptygame_score` field.
Where is my code going wrong?

Answer 1

you can also use decode function like this —

SELECT game_id, 
SUM(DECODE(game_score, null, 0, 0, -1, 1, 0)) AS score 
FROM .... 
WHERE .... 
GROUP BY ....

I have checked this query for working, its fine
hope it helps you….