在 SQL Server 的树中查找给定 ID 的所有父级

Question

我在单个表中有一个树结构，在另一个表中有项目关系。我需要从给定的项目中找出所有的父母。

SELECT Id FROM dbo.Items WHERE Selected = 1

由于我从该查询中得到 6,9,11，我需要返回 7、5、2 的父项 ID。

我认为我应该为此使用某种递归 CTE，但我不确定从哪里开始。

你能帮帮我吗？谢谢！

dbo.Relationship
Id       ParentId
3           6
6           7
8           7
7           2
4           9
9           5
5           2   


dbo.Items
Id              Selected
2                   0
3                   0
4                   0
5                   0
6                   1
7                   0
8                   0
9                   1
11                  1

Answer 1

在项目和关系之间的相关 Id 上左连接。

SELECT 
    Items.Id, 
    Relationship.ParentId 
FROM Items
LEFT JOIN Relationship ON Relationship.Id = Items.Id

我过去曾使用它来获取所有父 ID：

with compParent as
(
    select * from Component Where ComponentId = @ComponentId
    union all
    select Component.* from Component join compParent on Component.ComponentId = 
    compParent.ContainerParentId
)

select * from compParent;

我已经用它来获取所有孩子：

with compChild as
(
    select * from Component where ComponentId = @ParentId
    union all
    select Component.* from Component join compChild on Component.ContainerParentId = compChild.ComponentId
)


select * from compChild;

您还可以查看已经发布的许多 stackOverFlow 帖子，以获得父母和/或孩子。或者简单的谷歌搜索“SQL Server Get Parents”

Answer 2

您想获取所选项目的所有父项吗？ 我改为使用临时表。

if object_id('tempdb..#Relationship') is not null drop table #Relationship
create table #Relationship(Id int,ParentId int)
insert into #Relationship(Id,ParentId)
SELECT 3,6 UNION
SELECT 6,7 UNION
SELECT 8,7 UNION
SELECT 7,2 UNION
SELECT 4,9 UNION
SELECT 9,5 UNION
SELECT 5,2
if object_id('tempdb..#items') is not null drop table #items
create table #items(Id int, Selected bit)
insert into #items(Id,Selected)
SELECT 2,0 UNION
SELECT 3,0 UNION
SELECT 4,0 UNION
SELECT 5,0 UNION
SELECT 6,1 UNION
SELECT 7,0 UNION
SELECT 8,0 UNION
SELECT 9,1 UNION
SELECT 11,1

;with cte AS (
   SELECT i.ID AS SelectedID,r.ParentId FROM #Items AS i INNER JOIN #Relationship AS r ON i.id=r.id WHERE i.Selected=1
   UNION ALL
   SELECT cte.SelectedID, r.ParentId FROM #Relationship AS r INNER JOIN CTE ON CTE.ParentId=r.id
)
SELECT * FROM cte ORDER BY cte.SelectedID

它能给你一些帮助吗？

SelectedID ParentId ------------ ------------ 6 7 6 2 9 5 9 2