SQL recursive hierarchy - sql

Question

I am struggling to get one recursive CTE to work as desired but still with no chance..
So, I have the following similar table structures:
tblMapping:
map_id | type_id | name | parent_id
1 1 A1 0
2 1 A2 0
3 1 A3 1
4 1 A4 3
5 2 B1 0
6 2 B2 5
7 2 B3 6
8 1 A5 4
9 2 B4 0
tblRoleGroup:
role_group_id | type_id | map_id | desc_id
1 1 0 null
1 2 0 null
2 1 3 1
2 2 6 0
3 1 8 1
3 2 9 1
In tblRoleGroup, the desc_id field means:
null - allow all (used only in combination with map_id=0)
0 - allow all from parent including parent
1 - allow only current node
Still in tblRoleGroup if map_id=0 then the query should get all elements from same type_id
The query result should look like this:
role_group_id | type_id | map_id | path
1 1 1 A1
1 1 2 A2
1 1 3 A1.A3
1 1 4 A1.A3.A4
1 1 8 A1.A3.A4.A5
1 2 5 B1
1 2 6 B1.B2
1 2 7 B1.B2.B3
1 2 9 B4
2 1 3 A1.A3
2 2 6 B1.B2
2 2 7 B1.B2.B3
3 1 8 A1.A3.A4.A5
3 2 9 B4
The query below solves only a part of the expected result, but I wasn't able to make it work as the expected result..
WITH Hierarchy(map_id, type_id, name, Path) AS
(
SELECT t.map_id, t.type_id, t.name, CAST(t.name AS varchar(MAX)) AS Expr1
FROM dbo.tblMapping AS t
LEFT JOIN dbo.tblMapping AS t1 ON t1.map_id = t.parent_id
WHERE (t1.parent_id=0)
UNION ALL
SELECT t.map_id, t.type_id, t.name, CAST(h.Path + '.' + t.name AS varchar(MAX)) AS Expr1
FROM Hierarchy AS h
JOIN dbo.tblMapping AS t ON t.parent_id = h.map_id
)
SELECT h.map_id, h.type_id, t.role_group_id, h.Path AS Path
FROM Hierarchy AS h
LEFT JOIN dbo.tblRoleGroup t ON t.map_id = h.map_id
Could someone help me on this?
Thank you

Answer 1

At first I create a function that brings all descendants of passed map_id:
CREATE FUNCTION mapping (#map_id int)
RETURNS TABLE
AS
RETURN
(
WITH rec AS (
SELECT map_id,
[type_id],
CAST(name as nvarchar(max)) as name,
parent_id
FROM tblMapping
WHERE map_id = #map_id
UNION ALL
SELECT m.map_id,
m.[type_id],
r.name+'.'+m.name,
m.parent_id
FROM rec r
INNER JOIN tblMapping m
ON m.parent_id = r.map_id
)
SELECT *
FROM rec
);
GO
Then run this:
;WITH rec AS (
SELECT map_id,
[type_id],
CAST(name as nvarchar(max)) as name,
parent_id
FROM tblMapping
WHERE parent_id=0
UNION ALL
SELECT m.map_id,
m.[type_id],
r.name+'.'+m.name,
m.parent_id
FROM rec r
INNER JOIN tblMapping m
ON m.parent_id = r.map_id
)
SELECT t.role_group_id,
r.[type_id],
r.map_id,
r.name as [path]
FROM tblRoleGroup t
CROSS JOIN rec r
WHERE r.[type_id] = CASE WHEN t.desc_id IS NULL AND t.map_id = 0 THEN t.[type_id] ELSE NULL END
OR r.map_id = CASE WHEN t.desc_id = 1 THEN t.map_id ELSE NULL END
OR r.map_id IN (
SELECT map_id
FROM dbo.mapping (CASE WHEN t.desc_id = 0 THEN t.map_id ELSE NULL END)
)
ORDER BY role_group_id, r.[type_id], r.map_id
Will give you:
role_group_id type_id map_id path
1 1 1 A1
1 1 2 A2
1 1 3 A1.A3
1 1 4 A1.A3.A4
1 1 8 A1.A3.A4.A5
1 2 5 B1
1 2 6 B1.B2
1 2 7 B1.B2.B3
1 2 9 B4
2 1 3 A1.A3
2 2 6 B1.B2
2 2 7 B1.B2.B3
3 1 8 A1.A3.A4.A5
3 2 9 B4