Question

我有一张桌子（称之为结果），比如锦标赛的分数：

id | Winner | Loser | Score
---+--------+-------+------
1    Bob      Joe     4
2    Roy      Mary    3
3    Joe      Roy     6
4    Mary     Bob     1
5    Ellen    Roy     9
6    José     Roy     2
7    Joe      Bob     7

我想要做的是计算每个名字成为胜利者的次数，以及每次他们是输家的次数，并根据所玩的游戏次数来降序：

Name | Wins | Losses | NumberGames
-----+------+--------+------------
Roy    1     3         4
Bob    1     2         3
Joe    2     1         3
Mary   1     1         2
Ellen  1     0         1
José   1     0         1

更好的是，我想根据赢得的比赛百分比除以比赛总数（胜利加损失）来降序。

我不想对任何名称进行硬编码，例如获胜者=＆＃34; Bob＆＃34;。

我知道如何制定一个查询来计算每个列，但我还没想出如何创建3个不同的计数并按名称进行分组。

Answer 1

我想要做的是计算每个名字的次数赢家，每次他们是输家，并命令它下降比赛次数：

此查询的工作原理是根据带有查询的Winner和Loser列生成唯一的名称列表。

<强>查询

SELECT
 DISTINCT
  Results.Winner AS name
 FROM 
  Results

UNION 

SELECT
 DISTINCT
  Results.Loser AS name
 FROM 
  Results

LEFT JOIN是Winner和Loser COUNT的唯一名单，以获得胜利和失败。

<强>查询

SELECT
   Results_Wins_Losses.name
 , Results_Wins_Losses.Wins 
 , Results_Wins_Losses.Losses 
 , (Results_Wins_Losses.Wins + Results_Wins_Losses.Losses) AS NumberGames
FROM ( 

  SELECT 
     unique_result_names.name
   , (
      CASE
         WHEN results_wins.Wins IS NULL
         THEN 0
         ELSE results_wins.Wins
       END
      ) AS Wins 
   , (
      CASE
         WHEN results_losses.Losses IS NULL
         THEN 0
         ELSE results_losses.Losses
       END
      ) AS Losses   
  FROM ( 
    SELECT
     DISTINCT
      Results.Winner AS name
     FROM 
      Results

    UNION 

    SELECT
     DISTINCT
      Results.Loser AS name
     FROM 
      Results 

  ) AS unique_result_names

  LEFT JOIN (
    SELECT
       Results.Winner
     , COUNT(*) AS Wins
    FROM  
     Results
    GROUP BY
     Results.Winner
  ) AS results_wins 
  ON
   unique_result_names.name = results_wins.Winner

  LEFT JOIN (
    SELECT
       Results.Loser
     , COUNT(*) AS Losses
    FROM  
     Results
    GROUP BY
     Results.Loser
  ) AS results_losses
  ON
   unique_result_names.name = results_losses.Loser
) AS Results_Wins_Losses
ORDER BY 
 NumberGames DESC

<强>结果

|  name | Wins | Losses | NumberGames |
|-------|------|--------|-------------|
|   Roy |    1 |      3 |           4 |
|   Bob |    1 |      2 |           3 |
|   Joe |    2 |      1 |           3 |
|  Mary |    1 |      1 |           2 |
| Ellen |    1 |      0 |           1 |
|  José |    1 |      0 |           1 |

参见演示http://sqlfiddle.com/#!9/68abe/33

Answer 2

另一种方法：

SELECT  Name,
        SUM(Wins) AS Wins,
        SUM(Losses) AS Losses,
        SUM(Wins) + SUM(Losses) AS NumberGames
    FROM  
      (
        SELECT  winner AS Name, COUNT(*) AS Wins, 0 AS Losses
            FROM  Results
            GROUP BY  winner
        UNION  ALL 
        SELECT  loser AS Name,  0 AS Wins, COUNT(*) AS Losses
            FROM  Results
            GROUP BY  loser 
      )
    ORDER BY 4 DESC

计算两列中的值匹配，分别计算

2 个答案: