Access To Recursive Tree With Cte [closed] - sql

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I have 3 table of data: some people has access a branch(s) and branch can have some sub branches
Table Persons
ID PName
1 P1
2 P2
Table Branches
ID Title BrachIDRef
0 Master null
1 B1 0
2 B2 1
3 B3 2
4 B4 2
5 B5 1
6 B6 0
7 B7 6
Table PersonBranches
Id PersonIDref BranchIDref
1 1 1
2 2 6
3 2 2
And Result I need is Access of Persons to branches and Sub branches in SQL Server Query like this :
P1 B1
P1 (and All Childs of B1 - for each child have a record of data)
P2 B6
P2 and All Childs if B6
P2 B2
P2 and All Childs Of B2

Answer 1

You need to use recursive CTE for Branches table and you need to use ROW_NUMBER() for generate dynamic unique record ID, which will use order records.
Before UNION ALL select query generate parent record values with record ID.
After UNION ALL select query generate child records based on parent record.
Please check below query for your expected result.
SELECT * INTO #Persons
FROM (
SELECT '1' ID,'P1' PName UNION ALL
SELECT '2','P2') a
SELECT * INTO #Branches
FROM (
SELECT '0' ID,'Master' Title,NULL BrachIDRef UNION ALL
SELECT '1','B1','0' UNION ALL
SELECT '2','B2','1' UNION ALL
SELECT '3','B3','2' UNION ALL
SELECT '4','B4','2' UNION ALL
SELECT '5','B5','1' UNION ALL
SELECT '6','B6','0' UNION ALL
SELECT '7','B7','6'
) a
SELECT * INTO #PersonBranches
FROM (
SELECT '1' Id,'1' PersonIDref,'1' BranchIDref UNION ALL
SELECT '2' Id,'2' PersonIDref,'6' BranchIDref UNION ALL
SELECT '3' Id,'2' PersonIDref,'2' BranchIDref
) a
;WITH branchCTE
AS
(
SELECT
B.ID,B.Title,B.BrachIDRef,P.PName,ROW_NUMBER() OVER (ORDER BY B.BrachIDRef,B.ID) AS RID
FROM #Branches B
INNER JOIN #PersonBranches PB ON PB.BranchIDref = B.ID
INNER JOIN #Persons P ON P.ID = PB.PersonIDref
UNION ALL
SELECT
B1.ID,B1.Title,B1.BrachIDRef,C.PName,C.RID
FROM #Branches B1
INNER JOIN branchCTE C ON C.ID = B1.BrachIDRef
WHERE B1.BrachIDRef > 0
)
SELECT
C.PName,
C.Title
FROM branchCTE C
ORDER BY C.RID
DROP TABLE #Persons;
DROP TABLE #Branches;
DROP TABLE #PersonBranches;

Answer 2

You can use connect by prior with different CTE and union it with your normal query to fetch all the children as follows:
cte as
(SELECT ANCESTOR,
LISTAGG(case when Title = ANCESTOR then null else title end, '/') within group (order by null) as pth from
(SELECT DISTINCT ID,
CONNECT_BY_ROOT Title as ANCESTOR,
Title
FROM Branches
CONNECT BY PRIOR ID = BrachIDRef)
GROUP BY
ANCESTOR)
--
SELECT pb.id, p.pname, b.title
from PersonBranches pb
join persons p on (p.id = pb.PersonIDref)
join Branches b on (pb.BranchIDref = b.id)
union all
SELECT pb.id, p.pname, c.pth
from PersonBranches pb
join persons p on (p.id = pb.PersonIDref)
join Branches b on (pb.BranchIDref = b.id)
join cte c on (b.title = c.ANCESTOR)
order by id;
db<>fiddle demo
Cheers!!