用于递归查询的 CTE

Question

我正在尝试使用 CTE 查询分层数据，但我遇到了以下情况。我的数据库中有以下数据：

dbo.ProjectComponents

Id
207

dbo.ProjectAccessories

Id  ProjectComponentId  AccessorySetId
4   34                  NULL
5   145                 NULL
6   207                 NULL
8   NULL                3

dbo.ProjectAccessorySets

Id  AccessoryId
1   NULL
2   NULL
3   6

我想在所有 dbo.ProjectAccessory.Id 中查询一个 ProjectComponent。

以下查询引发此错误：Error 530: The statement terminated. The maximum recursion 100 has been exhausted before statement completion.

WITH AccessoryIds AS
(SELECT parent.Id, accessorySets.AccessoryId
FROM dbo.ProjectAccessories AS parent, dbo.ProjectAccessorySets AS accessorySets
WHERE parent.ProjectComponentId = 207 AND accessorySets.AccessoryId = parent.Id
UNION ALL
SELECT child.Id, childAccessorySets.AccessoryId
FROM dbo.ProjectAccessories AS child, dbo.ProjectAccessorySets AS childAccessorySets
INNER JOIN AccessoryIds AS asi ON childAccessorySets.AccessoryId = asi.Id
WHERE childAccessorySets.AccessoryId = child.Id AND childAccessorySets.AccessoryId IS NOT NULL)
SELECT * FROM AccessoryIds

预期输出

Id  AccessoryId
6   NULL
8   6

编辑

添加 option (maxrecursion 0) 并没有解决问题，并且永远取消查询运行。除此之外，我数据库中的递归深度目前只有 2（查看添加的数据）

Answer 1

看起来这样就可以了：

DECLARE @ProjectAccessories TABLE
(
    Id INT, ProjectComponentId INT, AccessorySetId INT 
)
DECLARE @ProjectAccessorySets TABLE
(
    Id INT, AccessoryId INT
)

INSERT @ProjectAccessories (Id, ProjectComponentId, AccessorySetId)
VALUES (4, 34, NULL)
,       (5, 145, NULL)
,       (6, 207, NULL)
,       (8, NULL, 3)

INSERT @ProjectAccessorySets (Id, AccessoryId)
VALUES (1, NULL)
,       (2, NULL)
,       (3, 6) 

;
WITH AccessoryIds AS
(
        SELECT      parent.Id
        ,           parent.AccessorySetId AS AccessoryId
        FROM        @ProjectAccessories AS parent
        INNER JOIN  @ProjectAccessorySets AS accessorySets
                ON  accessorySets.AccessoryId = parent.Id
        WHERE       parent.ProjectComponentId = 207

        UNION ALL

        SELECT      child.id
        ,           childAccessorySets.AccessoryId
        FROM        AccessoryIds AS asi 
        INNER JOIN  @ProjectAccessorySets AS childAccessorySets
                ON  childAccessorySets.AccessoryId = asi.Id
        INNER JOIN  @ProjectAccessories AS child
                ON  child.AccessorySetId = childAccessorySets.id
)

SELECT  * 
FROM    AccessoryIds

结果：

+----+-------------+
| Id | AccessoryId |
+----+-------------+
|  6 | NULL        |
|  8 | 6           |
+----+-------------+

用于递归查询的 CTE

CTE for recursive querying

sql

sql-server

recursive-query

common-table-expression