SELECT DISTINCT from multiple columns - mysql

Question

This is a bit of a complex query, but I have a database of snooker matches, and am trying to generate stats on who has played and won the most deciding frames (don't worry about the rules if you don't know the game).
Table:
ID player1 player2 bestOf player1Score player2Score
1 1 2 9 5 0
2 2 1 9 5 4
3 1 2 9 5 4
4 2 1 9 4 5
What I am trying to do is something like the following:
SELECT COUNT(*) AS played, DISTINCT(player1,player2) AS playerID
FROM matches
WHERE (player1Score=BestOf / 2 + 0.5 AND player2Score=BestOf / 2 - 0.5)
GROUP BY playerID
The above query doesn't work, as I believe DISTINCT doesn't support multiple columns. The result I'm looking for from the top table is:
playerID played won
1 3 2
2 3 1
The top row in the table is not displayed, as it is not a final frame.
I have tried variations such as:
SELECT GROUP(player1,player2)
SELECT player1 + player2 AS playerID, select DISTINCT(playerID)
SELECT (player1 + player2) AS playerID GROUP BY playerID
and a good few others. Any hint would be appreciated!

Answer 1

I don't actually have your tables with me so my sql probably has lots of syntax errors. But hopefully I will be to get the general idea across.
We can compute the list of deciding frame games where player1 won and union it with the list of deciding frame games where player2 won. As long as we rename the winner's column name to the same string ('player'), the union of these tables should yield a single table marking out the number of times each person won.
select player, count(*) as num_won from ((select player1 as player from matches where player1Score - player2Score = 1) union (select player2 as player from matches where player2Score - player1Score = 1));
This should give you a mapping from each player's id to the number of times they won.
Then consider
select player, count(*) as num_played from ((select player1 as player from matches where abs(player1Score - player2Score) = 1) union (select player2 as player from matches where abs(player2Score - player1Score) = 1));
The use of the abs function should help you discover the number of deciding frame games each player played. Now we combine these two tables to get your final answer
select players_table.player, players_table.num_played, winners_table.num_won from (select player, count(*) as num_won from ((select player1 as player from matches where player1Score - player2Score = 1) union (select player2 as player from matches where player2Score - player1Score = 1)) winners_table), (select player, count(*) as num_played from ((select player1 as player from matches where abs(player1Score - player2Score) = 1) union (select player2 as player from matches where abs(player2Score - player1Score) = 1)) players_table) where winners_table.player == players_table.player;

Answer 2

create table temp_score
select playerid, count(*) as won
FROM(
Select case when player1score > player2score then player1 else player2 end as playerid
from score
where
(player2Score=Round(BestOf / 2 + 0.5,0) AND player1Score=round(BestOf / 2 - 0.5,0))
or
(player1Score=Round(BestOf / 2 + 0.5,0) AND player2Score=round(BestOf / 2 - 0.5,0))
) a
group by playerid
Select playerid,won, (Select SUM(won) from temp_score) as TotalPlayed from temp_score