Find all parents of given ids in tree in SQL Server - sql-server

Question

I have a tree structure in single table and item relationships in another table. I need to find out all the parents from the given items.
SELECT Id FROM dbo.Items WHERE Selected = 1
Since I get 6,9, 11 from that query, I would need to return parent item ids of those which are 7, 5, 2.
I think I should use some kind of recursive CTE for this, but I'm not sure where to start.
Could you help me out? Thanks!
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

Do you want to get all the parent of selected items?
I changed to use temporary table.
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
Can it give you some help?
SelectedID ParentId
----------- -----------
6 7
6 2
9 5
9 2

Answer 2

Left Join on the related Id between Items and Relations.
SELECT
Items.Id,
Relationship.ParentId
FROM Items
LEFT JOIN Relationship ON Relationship.Id = Items.Id
I have used this in the past to get all parent Ids:
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;
I have used this to get all children:
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;
You can also look at the many stackOverFlow posts that are already out there to get parent and/or children. Or a simple google search for "SQL Server Get Parents"