递归和SQL Server

问题描述

我需要在SQL Server中进行递归求和。我想要一个存储过程，我可以在其中传递一个父ID，然后返回链接到该父ID的所有子项(以及子项的子项)的总计。

这是我到目前为止所拥有的

IF object_id('tempdb..#Averages') IS NOT NULL
BEGIN
   DROP TABLE #Averages
END


CREATE TABLE #Averages
(
ID INT PRIMARY KEY CLUSTERED IDENTITY(1,1),
Name VARCHAR(255),
ParentID int,
Value INT
)

INSERT INTO #Averages(Name,ParentID,Value)VALUES('Fred',NULL,1)
INSERT INTO #Averages(Name,ParentID,Value)VALUES('Bets',NULL,1)

INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Wynand',ID,21 FROM #Averages WHERE      Name = 'Fred'  )

INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Dewald',ID,27 FROM #Averages WHERE     Name = 'Fred'  )
INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Katelynn',ID,1 FROM #Averages WHERE Name = 'Dewald'  )

INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Jacques',ID,28 FROM #Averages WHERE Name = 'Bets'  )
INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Luan',ID,4 FROM #Averages WHERE Name = 'Jacques'  )
INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Ruben',ID,2 FROM #Averages WHERE Name = 'Jacques'  )


;WITH Personal AS
(
SELECT N=1, ID,Name,ParentID,Value
FROM #Averages 
WHERE ParentID IS NULL
UNION ALL
SELECT N+1, Av.ID,Av.Name,Av.ParentID,Av.Value
FROM #Averages Av
INNER JOIN  Personal P ON P.ID = Av.ParentID
)

SELECT Name,
    SUM(Value) as Total
FROM Personal
WHERE N<=3
GROUP BY Name

推荐答案

玩了一会儿后，我想我明白了。我添加了一个顶级ID，它是我在CTE的Root中设置的。然后只需添加所有递归的顶级id。

最后我只求和，基本上使用TopLevelId连接顶层表。

IF object_id('tempdb..#Averages') IS NOT NULL
BEGIN
   DROP TABLE #Averages
END

CREATE TABLE #Averages
(
    ID INT PRIMARY KEY CLUSTERED IDENTITY(1,1),
    Name VARCHAR(255),
    ParentID int,
    Value INT
)

 INSERT INTO #Averages(Name,ParentID,Value)VALUES('Fred',NULL,1)
 INSERT INTO #Averages(Name,ParentID,Value)VALUES('Bets',NULL,1)

 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Wynand',ID,21 FROM #Averages WHERE Name = 'Fred'  )

 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Dewald',ID,27 FROM #Averages WHERE Name = 'Fred'  )
 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Katelynn',ID,1 FROM #Averages WHERE Name = 'Dewald'  )

 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Jacques',ID,28 FROM #Averages WHERE Name = 'Bets'  )
 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Luan',ID,4 FROM #Averages WHERE Name = 'Jacques'  )
 INSERT INTO #Averages(Name,ParentID,Value)(SELECT 'Ruben',ID,2 FROM #Averages WHERE Name = 'Jacques'  )


;WITH Personal AS
(
    SELECT N=1, 
        ID,
        Name,
        ParentID,
        Value,
        TopLevelID =ID
    FROM #Averages 
    WHERE ParentID IS NULL

    UNION ALL

    SELECT N+1, 
        Av.ID,
        Av.Name,
        Av.ParentID,
        Av.Value,
        TopLevelID =P.TopLevelID
    FROM #Averages Av
    INNER JOIN  Personal P ON P.ID = Av.ParentID
)

SELECT SUM(P.Value) AS Total,
        A.Name
FROM Personal P
INNER JOIN #Averages A on A.ID = P.TopLevelID
GROUP BY A.Name