在SQL Server中生成錦標賽賽程表

我需要一個表格，其名稱爲偶數個團隊，並且這些表格會生成一個錦標賽的時間表，即如果有4個團隊：team1，team2，team3和team4該表的名稱，那麼結果表看起來像下面的在SQL Server中生成錦標賽賽程表

Team Team  Round 
----------------------- 
team1 team2 1 
team 3 team4 1 
team1 team3 2 
team2 team4 2 
team1 team4 3 
team2 team3 3

我需要使用T-SQL來做到這一點。我曾嘗試使用Round Robin Tournament算法，但我不知道如何在T-SQL中實現它。

來源

2017-04-17 asanchez121143

看到，因爲沒有其他人給了這個答案，我想我也可以告訴你一個使用動態SQL這樣的（可能是低效的）方式：

DECLARE @SQL NVARCHAR(MAX) = N''; 
SELECT TOP (SELECT CASE COUNT(*) % 2 WHEN 1 THEN COUNT(*) ELSE COUNT(*) - 1 END FROM dbo.Teams) @SQL += N' UNION ALL 
SELECT * 
FROM 
(
    SELECT TOP (SELECT COUNT(*)/2 FROM T) 
     Team, 
     RN, 
     RoundNum = ' + CAST(N AS NVARCHAR(3)) + N', 
     Match = ROW_NUMBER() OVER (ORDER BY CASE WHEN RN = 1 THEN 0 ELSE 1 END, (RN + ' + CAST(N - 2 AS NVARCHAR(3)) + N') % (SELECT COUNT(*) FROM T)), 
     Slot = 1 
    FROM T 
    ORDER BY CASE WHEN RN = 1 THEN 0 ELSE 1 END, (RN + ' + CAST(N - 2 AS NVARCHAR(3)) + N') % (SELECT COUNT(*) FROM T) 
    UNION ALL 
    SELECT TOP (SELECT COUNT(*)/2 FROM T) 
     Team, 
     RN, 
     RoundNum = ' + CAST(N AS NVARCHAR(3)) + N', 
     Match = ROW_NUMBER() OVER (ORDER BY CASE WHEN RN = 1 THEN 1 ELSE 0 END, (RN + ' + CAST(N - 2 AS NVARCHAR(3)) + N') % (SELECT COUNT(*) FROM T) DESC), 
     Slot = 2 
    FROM T 
    ORDER BY CASE WHEN RN = 1 THEN 1 ELSE 0 END, (RN + ' + CAST(N - 2 AS NVARCHAR(3)) + N') % (SELECT COUNT(*) FROM T) DESC 
) AS T 
' 
FROM (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM sys.objects) T(N) 
ORDER BY N; 

SELECT @SQL = N' 
WITH T AS 
(
    SELECT Team, RN = ROW_NUMBER() OVER (ORDER BY Team) 
    FROM dbo.Teams 
    UNION ALL 
    SELECT ''Bye'', COUNT(*) + 1 
    FROM dbo.Teams 
    HAVING COUNT(*) % 2 = 1 
), 
CTE2 AS 
(
' + STUFF(@SQL, 1, 11, '') + N' 
) 
SELECT T1.RoundNum, T1.Match, Team1 = T1.Team, Team2 = T2.Team 
FROM 
(
    SELECT * 
    FROM CTE2 
    WHERE Slot = 1 
) AS T1 JOIN 
(
    SELECT * 
    FROM CTE2 
    WHERE Slot = 2 
) AS T2 
    ON T2.RoundNum = T1.RoundNum 
    AND T2.Match = T1.Match;'; 


EXEC sp_executesql @SQL;

從本質上講，它的fix one of the contributors in the first or last column of the table描述在你的維基鏈接中，通過紮根1並將所有團隊轉移到1左右。對於奇數團隊，它會添加一個「再見」對手。而且它只是在表格中循環N或N-1次（取決於是否有偶數或奇數的球隊）。

來源

2017-04-18 05:05:41 ZLK

在SQL Server中生成錦標賽賽程表

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