Question

I have a table named games:

id  player_a_id  player_b_id  player_a_result  player_b_result  turn 
 1     1           2             1                 0              1 
 2     3           4             1                 0              1 
 3     1           3             1                 0              2

I am trying to write a SQL query that will make a rating list of the table. Like this:

player_id  total score 
   1           2 
   2           0 
   3           1 
   4           0 

I am not sure how to write the sql. Some help would be great!

Answer 1

SELECT player_id, SUM(result)
FROM
(SELECT player_a_id AS player_id, player_a_result AS result FROM games
UNION
SELECT player_b_id, player_b_result FROM games) AS u
GROUP BY player_id
ORDER BY player_id

This is what I’m guessing you’re after. This creates a subquery (the stuff in parens()) that combines (UNION) players a and b into one set, then groups by player and sums the results.