SQL 服务器：select 只有第一个多列记录实例

Question

我正在尝试从记分系统中获取一些个人统计数据。从本质上讲，球队被安排参加比赛

Match
---------
Matchid (uniqueidentifier)
SessionId (int)
WeekNum (int)

这些比赛被分成几组，一组中的两名特定球员互相比赛

MatchSet
-----------
SetId (int)
Matchid (uniqueidentifier)
HomePlayer (int)
AwayPlayer (int)
WinningPlayer (int)
LosingPlayer (int)
WinningPoints (int)
LosingPoints (int)
MatchEndTime (datetime)

为了允许球员缺席，每场比赛允许球员上场两次。每局的分数将计入他们的团队总分，但对于个人奖项，只计算球员第一次上场的时间。

我一直在尝试使用 CTE 对行进行编号

;WITH cte AS
(
   SELECT *,
       ROW_NUMBER() OVER (PARTITION BY MatchId ORDER BY MatchEndTime) AS rn
   FROM 
       (SELECT 
            SetId, MS.MatchId, WinningPlayer, LosingPlayer, 
            HomePlayer, AwayPlayer, WinningPoints, LosingPoints, MatchEndTime
        FROM 
            MatchSet MS 
        INNER JOIN 
            [Match] M ON M.MatchId = MS.MatchId AND M.[Session] = @SessionId
    )

但我很纠结，因为玩家可能是给定盘中的主场玩家或客场玩家（也可能是赢家或输家）

理想情况下，然后可以根据 WinningPlayer 或 LosingPlayer 将此结果加入回玩家 table，这样我就可以得到个人排名列表

Answer 1

也许您可以虚拟化数据的规范化视图并关闭它而不是 MatchSet table。

;WITH TeamPlayerMatch AS
(
    SELECT TeamID,PlayerID=WinnningPlayer,MatchID,Points = MS.WinningPoints, IsWinner=1 FROM MatchSet MS INNER JOIN TeamPlayer T ON T.PlayerID=HomePlayer
    UNION ALL
    SELECT TeamID,PlayerID=LosingPlayer,MatchID,Points = MS.LosingPoints, IsWinner=0 FROM MatchSet MS INNER JOIN TeamPlayer T ON T.PlayerID=AwayPlayer
)

,cte AS
(
   SELECT *,
       ROW_NUMBER() OVER (PARTITION BY MatchId ORDER BY MatchEndTime) AS rn
   FROM 
       (SELECT 
            SetId, MS.MatchId, PlayerID, TeamID, Points, MatchEndTime, IsWinner
        FROM 
            TeamPlayerMatch MS 
        INNER JOIN 
            [Match] M ON M.MatchId = MS.MatchId AND M.[Session] = @SessionId
        WHERE
            IsWinner=1
    )

Answer 2

我认为第一步是编写几个 CTE，将数据放入一个结构中，您可以在其中评估玩家点数，而不管 win/loss。这是一个可能的开始：

;with PlayersPoints as 
(
   select m.MatchId
        ,m.SessionId 
        ,m.WeekNum
        ,ms.SetId       
        ,ms.WinningPlayer as PlayerId
        ,ms.WinningPoints as Points
        ,'W' as Outcome
        ,ms.MatchEndTime 
    from MatchSet ms
    join Match m on on ms.MatchId = m.MatchId
        and m.SessionId = @SessionId 

   union all 

   select m.MatchId
        ,m.SessionId 
        ,m.WeekNum
        ,ms.SetId   
        ,ms.LosingPlayer as PlayerId
        ,ms.LosingPoints as Points
        ,'L' as Outcome
        ,ms.MatchEndTime 
    from MatchSet ms
   join Match m on on ms.MatchId = m.MatchId
        and m.SessionId = @SessionId 
)
, PlayerMatch as 
(
   select SetId
        ,WeekNum
        ,MatchId
        ,PlayerId
        ,row_number() over (partition by PlayerId, WeekNum order by MatchEndTime) as PlayerMatchSequence
    from PlayerPoints 
)
....

第一个 CTE 为每个玩家拉出分数，第二个 CTE 确定是哪场比赛。因此，为了计算单个点，您需要寻找 PlayerMatchSequence = 1。

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