遞歸SUM Sql服務器

Question

我需要在SQL Server中進行遞歸求和。我想要一個存儲過程，我可以傳入一個父ID，然後返回所有與該父ID相鏈接的子（和子的孩子）的總數。

這裏是我迄今爲止

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 

Answer 1

玩了一下後，我想我明白了。我添加了一個頂級ID，這是我在CTE的Root中設置的。然後，只需爲所有遞歸添加頂級ID。

最後我只求和，基本上用TopLevelId加入頂層表。

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 

Answer 2

這裏實現你想要的東西的一種方式，儘管它的做法略有不同，你有以上：

SQLFiddle

Create Table #Ancestors (
    ID int 
    , Name VARCHAR(255) 
    , ParentID int 
    , AncestryCompleteTF tinyint 
    , Ancestors varchar(max) 
    , TotalValue int  
) 

INSERT INTO #Ancestors 
SELECT 
    ID 
    , Name 
    , ParentID 
    , CASE ISNULL(ParentID, 0) 
    WHEN 0 THEN 1 
    ELSE 0 
    END 
    , CONVERT(VARCHAR, ISNULL(ParentID, '')) 
    , Value 
FROM 
    Averages 

WHILE EXISTS (SELECT * FROM #Ancestors WHERE AncestryCompleteTF = 0) 
BEGIN 
    UPDATE C SET 
    C.Ancestors = P.Ancestors + ',' + CONVERT(VARCHAR, P.ID), 
    C.AncestryCompleteTF = 1, 
    C.TotalValue = P.TotalValue + C.TotalValue 
    FROM #Ancestors C 
    INNER JOIN #Ancestors P ON (C.ParentID = P.ID) 
    AND P.AncestryCompleteTF = 1 
END 

SELECT 
    Name 
, TotalValue 
FROM 
    #Ancestors 

基本上我創建了一個臨時表，並使用一個while循環來更新已經計算出父代的行的總數（因爲這僅僅是一個廣告的例子將當前行的總數改爲父行的總數），直到所有行都已計算完畢。 ParentID爲空的行被設置爲開頭，所以他們的直接後代將首先計算，然後這些行的後代等。等等。