Question

我试图解决这个问题，我有两名玩家拥有游戏分数。查询应返回玩家的图表以及游戏数量，如果得分为3：0或0：3则得分为3的玩家获得3分，否则任何获胜为2分

我的表：

    player1        player2   player1score  player2score
    -------        -------   -------------  ------------
    john            lee           3             0 
    maria           andy          1             3
    andy            john          1             3

所需的表应该是这样的：

    players        gamesplayed   points  
    -------        -----------   ------
    john            2               5 
    andy            2               2
    maria           1               0
    lee             1               0

我有这个问题：

SELECT DISTINCT players, count(*) gamesplayed
FROM (
    SELECT player1 AS players
    FROM table
    UNION
    SELECT player2 AS players
    FROM table
) players

但是上面的查询会在gamesplayed中单独返回所有玩家的计数，而不是单独返回。

有人能看到问题吗？我也不确定是否热门实施了points列。

非常感谢

Answer 1

现在我认为适合MySQL-Statement，只需将其更改为内联视图，没有mysql环境，如果语法不完全正确，则为pz借口：

SELECT player, 
    COUNT(player) AS gamesPlayed, SUM(score) score
FROM 
    (SELECT player1 AS player, 
        CASE 
            WHEN player1score - player2score > 2 THEN  + 3
            WHEN player1score - player2score > 0 THEN +2
            ELSE + 0
            END as score 
        FROM playerTable
    UNION ALL
    SELECT player2 AS player, 
        CASE 
        WHEN player2score - player1score > 2 THEN  + 3
        WHEN player2score - player1score > 0 THEN +2
        ELSE + 0
        END AS score
    FROM playerTable) 
    AS playerSel
Group by player;

Answer 2

部分困难在于你使用的UNION会得到不同的值 - 所以如果玩家将游戏作为玩家1玩，而另一游戏作为玩家2玩，那么他只会被计算一次。另外，如果他作为球员1打了两场比赛，他只会被计算一次！

我认为您需要以下内容：

SELECT p1.player, COUNT(*) AS games_played, SUM(p1.player_score) AS total_points
  FROM (
    SELECT player1 AS player, player1score AS player_score
      FROM mytable
     UNION ALL
    SELECT player2 AS player, player2score AS player_score
      FROM mytable
) p1
 GROUP BY p1.player;

UNION ALL会保留所有行，而不是像UNION那样只获取不同的行。

Answer 3

在SQL-Server中完成，如果它适用于MySql，则为dunno：

WITH playerSel AS(
    SELECT player1 AS player, 
        CASE 
            WHEN player1score - player2score > 2 THEN  + 3
            WHEN player1score - player2score > 0 THEN +2
            ELSE + 0
            END as score 
        FROM playerTable
    UNION ALL
    SELECT player2 AS player, 
        CASE 
        WHEN player2score - player1score > 2 THEN  + 3
        WHEN player2score - player1score > 0 THEN +2
        ELSE + 0
        END as score
    FROM playerTable)
SELECT player, 
    COUNT(player) AS gamesPlayed, SUM(score) score
FROM playerSel
Group by player;

我检索了以下信息：

和j; 2; 2 约翰; 2; 5 利; 1; 0 玛利亚; 1; 0

MYSQL - 如何在两列上返回唯一计数

3 个答案: