CTE遍历备份一个层次?
-
06-09-2019 - |
题
我可以找到一个层次数据模型给定记录的所有儿童(见下面的代码),但我不知道如何与给定的子ID穿越回了父/子链。任何人都可以点我在正确的方向弄清楚如何做到这一点?这是可能的LINQ to SQL的呢?
WITH TaskHierarchy (TaskID, [Subject], ParentID, HierarchyLevel, HierarchyPath) AS
(
-- Base case
SELECT
TaskID,
[Subject],
ParentID,
1 as HierarchyLevel,
CONVERT(VARCHAR(MAX),'/') AS HierarchyPath
FROM Task
WHERE TaskID = 2
UNION ALL
-- Recursive step
SELECT
t.TaskID,
t.Subject,
t.ParentID,
th.HierarchyLevel + 1 AS HierarchyLevel,
CONVERT(varchar(MAX),th.HierarchyPath + CONVERT(VARCHAR(32),t.ParentID) + '/') AS HierarchyPath
FROM Task t
INNER JOIN TaskHierarchy th ON
t.ParentID = th.TaskID
)
SELECT *
FROM TaskHierarchy
ORDER BY HierarchyLevel, [Subject]
解决方案
啊,我计算出来:
WITH Hierarchy(TaskID, [Subject], ParentID, IsProject, HLevel)
AS
(
SELECT
TaskID,
[Subject],
ParentID ,
IsProject,
0 as HLevel
FROM
Task
WHERE
TaskID = 59
UNION ALL
SELECT
SubDepartment.TaskID,
SubDepartment.[Subject],
SubDepartment.ParentID ,
SubDepartment.IsProject,
HLevel + 1
FROM
Task SubDepartment
INNER JOIN
Hierarchy ParentDepartment
ON
SubDepartment.TaskID = ParentDepartment.ParentID
)
SELECT
TaskID,
[Subject],
ParentID,
IsProject,
HLevel
FROM
Hierarchy
ORDER BY
HLevel DESC
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