Question

我想得到父母和他们的孩子数据，意味着先来父母然后他们的孩子，下面是我想要转换为父母和他们的孩子的查询

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'

我在下面尝试查询

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

执行这些查询后我收到此错误

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'.

然后我更改了我的查询并删除了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

然后我收到了这个错误

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

实际上它是按设计，阅读Guidelines for Defining and Using Recursive Common Table Expressions

以下项目不允许在a的CTE_query_definition中   递归成员：


SELECT DISTINCT

GROUP BY

HAVING

标量聚合

TOP

LEFT，RIGHT，OUTER JOIN（允许内部联接）

子查询

您必须将您的LEFT JOIN和COUNT从CTE查询中移出，将这些数据存储在其他地方（例如在临时表中），然后再使用那些具有CTE查询结果的数据。或者，您可以避免CTE查询，并为每个级别的父级单独执行此操作，存储在单独的临时表中并使用结果。希望有所帮助。

Sql父子查询不起作用

1 个答案: