Recursive CTE with hierarchy data - sql-server

Question

Sample data:
declare #docs table (docid int, name varchar(10), isfolder int)
declare #hierarchy table (childid int, parent varchar(10))
insert #docs values (1, 'Doc1', 0)
insert #docs values (2, 'Doc2', 0 )
insert #docs values (3, 'Folder1', 1 )
insert #docs values (4, 'Folder2', 1 )
insert #docs values (5, 'SubFolderA', 1 )
insert #docs values (6, 'SubFolderB', 1 )
insert #hierarchy values (1, 5)
insert #hierarchy values (1, 6)
insert #hierarchy values (2, 6)
insert #hierarchy values (5, 3)
insert #hierarchy values (6, 4)
I want to list the data above so I end up with the documents (isfolder = 0) and the folder paths that they are in.
Expected output:
DocId Name Path
--------------------------------------
1 Doc1 Folder1\SubFolderA
1 Doc1 Folder2\SubFolderB
2 Doc2 Folder2\SubFolderB
CTE
I started to write this next CTE as it said this can be used to create my output but I am wrong somewhere
;WITH folderCTE (docid, name) AS
(
-- Anchor member
SELECT docid, CAST(name AS varchar(max)) AS name
FROM #docs
WHERE isfolder = 0
UNION ALL
-- Recursive member that references expression_name.
SELECT d.docid, CAST(folderCTE.Name + '\' + d.name AS varchar(max)) AS name
FROM folderCTE
INNER JOIN #docs d ON d.docid = folderCTE.docid
)
-- references expression name
SELECT *
FROM folderCTE
Can anyone show me how I should be doing a CTE for this?

Answer 1

If you use a CTE which just expands the hierarchy for folders, and a second one to build the hierarchy, you can simply join to this to get the folder for your docs:
declare #docs table (docid int, name varchar(10), isfolder int)
declare #hierarchy table (childid int, parentid varchar(10))
insert #docs values (1, 'Doc1', 0)
insert #docs values (2, 'Doc2', 0 )
insert #docs values (3, 'Folder1', 1 )
insert #docs values (4, 'Folder2', 1 )
insert #docs values (5, 'SubFolderA', 1 )
insert #docs values (6, 'SubFolderB', 1 )
insert #docs values (7, 'SuperFold1', 1 )
insert #hierarchy values (1, 5)
insert #hierarchy values (1, 6)
insert #hierarchy values (2, 6)
insert #hierarchy values (5, 3)
insert #hierarchy values (6, 4)
insert #hierarchy values (3, 7)
;WITH folderCTE
AS
(
select docid, cast(name as nvarchar(max)) as name, parentid
from #docs d
left join #hierarchy h on d.docid=h.childid
where d.isfolder = 1
),
folderHierarchyCTE
as
(
select docid, cast(name as nvarchar(max)) as name
from folderCTE where parentid is null
union all
select d.docid, cast(p.name + '/' + d.name as nvarchar(max))
from folderCTE d
inner join folderHierarchyCTE p on d.parentid = p.docid
)
SELECT d.docid, d.name, f.name
FROM #docs d
inner join #hierarchy h on h.childid=d.docid
inner join folderHierarchyCTE f on h.parentid=f.docid
where d.isfolder = 0