MySQL的：SUM 3个记录每

Question

类别

我有下面的表：

dayoftheweek (VARCHAR) 
player (VARCHAR) 
score (INT) 

对于每个播放器，有或者3，4或5的分数。 我必须计算每位玩家每周最佳3分的平均值。

我正沿

SELECT dayoftheweek, player, (SUM(score)/3) AS average_score 
FROM (SELECT dayoftheweek, player, score 
     FROM scoretable 
     GROUP BY dayoftheweek, player 
     ORDER BY score 
     LIMIT 0, 3) AS query 

但（显然），只有给我的前三个记录总体思路思考.. 有人可以把我在正确的方向吗？

干杯，马塞尔

Answer 1

你应该能够编写：

SELECT dayoftheweek, 
     player, 
     (SELECT AVG(score) 
      FROM (SELECT inner.score 
        FROM scoretable AS inner 
        WHERE inner.dayoftheweek = outer.dayoftheweek 
        AND inner.player = outer.player 
        ORDER 
         BY inner.score DESC 
        LIMIT 3 
       ) 
     ) AS best_score_avg 
    FROM scoretable AS outer 
; 

（免责声明：没有测试）

请注意，我用ORDER BY ... DESC拿到三个最大得分，但如果这些是高尔夫分数或者其中最好的分数是至少那些，那么您将想要将DESC更改为ASC（或只是删除它）。