Get Max value and corresponding column

问题:

How can I get corresponding columns from a max query in mysql? I want find out how many wins a player has. I will find that out by doing a count of the number of games that player has won. The will be done by selecting the max value per game and resulting player_id. However I am not sure how to get the corresponding player_id.

I have

   id   |   game_id | player_id | score

    1   |     1     |     1     |   254
    2   |     1     |     2     |   194
    3   |     2     |     1     |   432
    4   |     2     |     2     |   298

回答1:

This query should get what you need:

SELECT
    player_id, game_id, score
FROM
(
    SELECT game_id,MAX(score) AS MaxScore
    FROM games
    GROUP BY game_id
) AS Winners
JOIN games
    ON (games.game_id = Winners.game_id AND games.score = Winners.MaxScore)

It assumes that a tie is a win for both players.

SQLFiddle

If you want to get just the player and their number of wins, you can use this query:

SELECT
    player_id, COUNT(*) AS wins
FROM
(
    SELECT game_id,MAX(score) AS MaxScore
    FROM games
    GROUP BY game_id
) AS Winners
JOIN games
    ON (games.game_id = Winners.game_id AND games.score = Winners.MaxScore)
WHERE player_id = {player_id}
GROUP BY player_id

Just replace {player_id} with the player you're looking for and wins is their number of wins or ties.