的SQL Server 2005 - CTE，保留值和數據集

Question

插入比方說你有一個表作爲這樣的（SQL SERVER 2005）

pairID childID parentID 
0  1  2 
1  2  3 
2  3  4 

你的CTE返回此數據集：

pairID childID parentID level 
0  1  2  2 
1  2  3  1 
2  3  4  0 

你如何保存初始子ID，這樣你會得到這樣的結果，而不是設置：

pairID childID parentID level 
0  1  2  2 
1  1  3  1 
2  1  4  0 

所以基本上什麼我做的是保持原來的子ID並返回一個，而不是其他...

這是CTE查詢到今天爲止，它完美的作品：

WITH TESTER AS (SELECT a.PairID, 
       a.ChildID, 
       a.ParentID, 
       0 AS Level 
       FROM 
       BusinessHierarchy AS a 
       LEFT OUTER JOIN BusinessHierarchy AS a2 
       ON a.ParentID = a2.ChildID 
       WHERE (a2.PairID IS NULL) 
       UNION ALL 
       SELECT b.PairID, b.ChildID, b.ParentID, oh.Level + 1 AS Level 
       FROM BusinessHierarchy AS b INNER JOIN 
       TESTER AS oh ON b.ParentID = oh.ChildID) 
SELECT PairID, ChildID, ParentID, Level 
FROM TESTER AS x 
ORDER BY Level, ChildID, ParentID 

Answer 1

你可以得到，如果第一（變成一個變量），然後再使用變量。

DECLARE @StartingId int 

SELECT 
    @StartingId = a.PairID 
FROM BusinessHierarchy AS a 
LEFT OUTER JOIN BusinessHierarchy AS a2 ON a.ParentID = a2.ChildID 
WHERE (a2.PairID IS NULL) 


WITH TESTER AS (SELECT a.PairID, 
      a.ChildID, 
      a.ParentID, 
      0 AS Level 
      FROM 
      BusinessHierarchy AS a 
      WHERE (a.PairID = @StartingId) 
      UNION ALL 
      SELECT b.PairID, b.ChildID, b.ParentID, oh.Level + 1 AS Level 
      FROM BusinessHierarchy AS b INNER JOIN 
      TESTER AS oh ON b.ParentID = oh.ChildID) 

SELECT PairID, @StartingId, ParentID, Level 
FROM TESTER AS x 
ORDER BY Level, ChildID, ParentID 

Answer 2

未經測試，但你試過嗎？

;WITH My_CTE AS 
(
    SELECT 
      BH1.PairID, 
      BH1.ChildID AS BaseID, 
      BH1.ChildID, 
      BH1.ParentID, 
      0 AS Level 
    FROM 
      BussinessHierarchy BH1 
    LEFT OUTER JOIN BussinessHierarchy BH2 ON 
      BH1.ParentID = BH2.ChildID 
    WHERE 
      BH2.PairID IS NULL 
    UNION ALL 
    SELECT 
      BH3.PairID, 
      CTE.BaseID, 
      BH3.ChildID, 
      BH3.ParentID, 
      CTE.Level + 1 AS Level 
    FROM 
      My_CTE CTE 
    INNER JOIN BussinessHierarchy BH3 ON 
      BH3.ParentID = CTE.ChildID 
    ) 
SELECT 
    PairID, 
    BaseID, 
    ParentID, 
    Level 
FROM 
    My_CTE 
ORDER BY 
    Level, 
    BaseID, 
    ParentID 

Answer 3

你寫的CTE只是把我搞糊塗了我害怕，所以我重寫了它，如下所示，它給出了你所要求的結果。這是否符合您的要求？

WITH List (pairID, childId, parentId, level, originalid) 
AS 
(
    -- Anchor member definition 
    select pairID, childID, parentID, 0 as level, ChildID as originalid 
    FROM  
    BusinessHeirarchy bh 
    where bh.PairID = 0 


    UNION ALL 

    -- Recursive member definition 
    select j.pairId, j.childID, j.parentID, lst.level +1 as level, lst.originalid 
    from BusinessHeirarchy j inner join List lst 
    on (lst.parentId = j.ChildID) 

) 

select * from list; 

可以很明顯的與輸出列，因爲你需要的順序播放，但你想要的數據相匹配。

有一件事要注意我的SQL是我限制基於零pairid的錨查詢，因爲您的示例數據沒有空值。這應該很容易改變，如果你需要空檢查拔出你的錨點。

然後，我只需加入父對子關係，並使用附加列OriginalId來持有錨定查詢中的第一個childId。