Question

首先，我知道这是一个非常模糊的标题 - 我对SQL的了解非常薄弱，以至于我真的不知道我要问的具体细节，所以请耐心等待。

我有一个看起来像这样的表：

+--------+-----------+----------+--------+--------+
| gameid | team1     | team2    | score1 | score2 |
+--------+-----------+----------+--------+--------+
|      1 | New York  | Boston   |      1 |      2 |
|      2 | New York  | Boston   |      2 |      0 |
|      3 | Baltimore | New York |      3 |      1 |
|      4 | Boston    | New York |      3 |      0 |
+--------+-----------+----------+--------+--------+

如果gameid是唯一标识符，则score1对应于team1等的分数

我需要的是一个查询，它将产生一个特定团队对所有对手的胜负总和。例如，使用纽约，查询将创建下表：

+-----------+------+--------+
| team      | wins | losses |
+-----------+------+--------+
| Baltimore |    0 |      1 |
| Boston    |    1 |      2 |
+-----------+------+--------+

Answer 1

我现在无法访问SQL框（所以这可能是语法弱点）而且我不是db结构的忠实粉丝，但这应该让你顺利：

SELECT team, SUM(win) AS wins, SUM(loss) AS losses
FROM
 (SELECT team1 AS team, 
   CASE WHEN score1>score2 THEN 1 END AS win, 
   CASE WHEN score2>score1 THEN 1 END AS loss
  FROM YourTable
  UNION ALL
  SELECT team2 AS team, 
   CASE WHEN score2>score1 THEN 1 END AS win, 
   CASE WHEN score1>score2 THEN 1 END AS loss
  FROM YourTable)
GROUP BY team

此外，这忽略了关系。

注意：我做了这个CW - 请更新，如果你可以改进它

Answer 2

这是可能的，但查询会变得非常复杂。如果可能，也许您可以重新组织模式以将更多信息编码到其中。例如，您可以team1和team2而不是winning_team和losing_team;同样地，使用winning_score和losing_score，您无需检查哪个分数与哪个团队相对应。然后你可以在GROUP BY上losing_team获得特定团队与其他团队的所有胜利，并在winning_team上获得一个以获得损失（并且完全避免使用得分）这个特殊的查询）。

Answer 3

同样来自@ David的评论，如果您的表结构更加规范化，这将会更容易，但是，使用模式，尝试此SQL

  Select T.Team,
     Sum(Case When S1.Score1 > S1.Score2 Or 
                   S2.Score2 > S2.Score1 Then 1 Else 0 End) Wins,
     Sum(Case When S1.Score1 < S1.Score2 Or 
                   S2.Score2 < S2.Score1 Then 1 Else 0 End Losses,
     Sum(Case When S1.Score1 = S1.Score2 Or 
                   S2.Score2 = S2.Score1 Then 1 Else 0 End Ties     
   (Select Distinct team1 team from Table
    Union Select Distinct team2 team from Table) T
      Left Join Table S1
         On S1.Team1 = T.Team
      Left Join Table S2
         On S2.Team2 = T.Team
  Group By T.Team

Answer 4

试试这个..

SELECT 
     team
    ,sum(wins) as wins
    ,sum(losses) as losses
FROM
    (
    SELECT 
         team1 as team
        ,SUM(CASE WHEN score1 > score2 THEN 1 ELSE 0 END) as wins
        ,SUM(CASE WHEN score1 < score2 THEN 1 ELSE 0 END) as losses
    FROM
        myTable
    GROUP BY
        team1
    UNION ALL
    SELECT 
         team2 as team
        ,SUM(CASE WHEN score2 > score1 THEN 1 ELSE 0 END) as wins
        ,SUM(CASE WHEN score2 < score1 THEN 1 ELSE 0 END) as losses
    FROM
        myTable
    GROUP BY
        team2 
    ) a
GROUP BY
team

帮助SELECT语句

4 个答案: