的Sql父子查詢不工作

Question

我希望得到家長和他們的孩子數據，意味着先到父母那麼他們的孩子的，下面是查詢，我要轉換爲父母和他們的孩子

SELECT a.FactorTitle, 
     a.FactorCode, 
     a.parentId, 
     c.FactorColumnCode, 
     c.FactorColumnTitle, 
     c.FactorColumnValue, 
     c.isFactorValue, 
     c.FieldType, 

    (SELECT count(*) 
    FROM FactorSetup 
    WHERE parentId=a.FactorCode) AS childCount 
FROM FactorSetup a 
INNER JOIN PDModelSetup b ON a.PDModelCode=b.PDModelCode 
LEFT JOIN FactorColumnSetup c ON a.FactorCode=c.FactorCode 
WHERE a.PDModelCode=2 
    AND c.isFactorValue <> 'Y' 
    AND a.FactorType='4' 

我試試下面查詢

WITH EntityChildren AS 
    (
    SELECT a.FactorTitle, 
      a.FactorCode, 
      a.parentId, 
      c.FactorColumnCode, 
      c.FactorColumnTitle, 
      c.FactorColumnValue, 
      c.isFactorValue, 
      c.FieldType, 

    (SELECT count(*) 
    FROM FactorSetup 
    WHERE parentId=a.FactorCode) AS childCount 
    FROM FactorSetup a 
    LEFT JOIN FactorColumnSetup c ON a.FactorCode=c.FactorCode 
    UNION ALL 
    SELECT a.FactorTitle, 
      a.FactorCode, 
      a.parentId, 
      c.FactorColumnCode, 
      c.FactorColumnTitle, 
      c.FactorColumnValue, 
      c.isFactorValue, 
      c.FieldType, 

    (SELECT count(*) 
    FROM FactorSetup 
    WHERE parentId=a.FactorCode) AS childCount 
    FROM FactorSetup a 

    INNER JOIN EntityChildren e2 ON a.parentId = e2.FactorCode 
    LEFT JOIN FactorColumnSetup c ON a.FactorCode=c.FactorCode 
    ) 

SELECT * FROM EntityChildren 

執行這些查詢後，我得到這個錯誤

Msg 467, Level 16, State 1, Line 1 
GROUP BY, HAVING, or aggregate functions are not allowed in the recursive part of a recursive common table expression 'EntityChildren'. 
Msg 462, Level 16, State 1, Line 1 
Outer join is not allowed in the recursive part of a recursive common table expression 'EntityChildren'. 

然後我改變我的查詢d拔下COUNT（*）

WITH EntityChildren AS 
    (
    SELECT a.FactorTitle, 
      a.FactorCode, 
      a.parentId, 
      c.FactorColumnCode, 
      c.FactorColumnTitle, 
      c.FactorColumnValue, 
      c.isFactorValue, 
      c.FieldType 
    FROM FactorSetup a 
    LEFT JOIN FactorColumnSetup c ON a.FactorCode=c.FactorCode 
    UNION ALL 
    SELECT a.FactorTitle, 
      a.FactorCode, 
      a.parentId, 
      c.FactorColumnCode, 
      c.FactorColumnTitle, 
      c.FactorColumnValue, 
      c.isFactorValue, 
      c.FieldType 
    FROM FactorSetup a 

    INNER JOIN EntityChildren e2 ON a.parentId = e2.FactorCode 
    LEFT JOIN FactorColumnSetup c ON a.FactorCode=c.FactorCode 
    ) 

SELECT * FROM EntityChildren 

然後我得到這個錯誤

Msg 462, Level 16, State 1, Line 1 
Outer join is not allowed in the recursive part of a recursive common table expression 'EntityChildren'. 

Answer 1

其實這是由設計，讀取Guidelines for Defining and Using Recursive Common Table Expressions

下列項目不允許在CTE_query_definition 遞歸成員：

• SELECT DISTINCT
• GROUP BY
• HAVING
• 標量聚合
• TOP
• LEFT，RIGHT，OUTER JOIN（INNER JOIN是允許的）
• 子查詢

您必須將您的LEFT JOIN和COUNT移出CTE查詢，並存儲這些數據一個別的地方（比如在一個臨時表中），然後使用那些與你的CTE查詢結果。或者，您可以避免CTE查詢，併爲每個父級子級別分步執行此操作，並將其存儲在單獨的臨時表中並使用結果。希望有所幫助。