SQL Server recursive query using MIN() - sql

Question

I'm trying to use MIN() function in my query to get minimum date from lower level of the tree nodes upward and check the date recursively but can't figure out how to do it using the MIN function.
So far I have written this query to get tree hierarchy:
WITH cteP AS
(
SELECT
WBS, WBSParent,
StartActual,
HierID = CONVERT(hierarchyid, CONCAT('/', WBS, '/'))
FROM
MSP.MSPMAIN
WHERE
ISNULL(#Top,-1) = CASE
WHEN #Top IS NULL
THEN ISNULL(WBSParent, -1)
ELSE WBS
END
UNION ALL
SELECT
WBS = r.WBS,
WBSParent = r.WBSParent,
StartActual = r.StartActual,
HierID = CONVERT(hierarchyid, CONCAT(p.HierID.ToString(), r.WBS, '/'))
FROM
MSP.MSPMAIN r
JOIN
cteP p ON r.WBSParent = p.WBS
)
SELECT
Lvl = HierID.GetLevel(),
WBS, WBSParent,
StartActual
FROM
cteP A
ORDER BY
A.HierID
Sample data
insert into MSPMAIN (WBSParent , WBS , StartActual) values
(NULL, 225, null)
,(225, 2251, null)
,(2251, 22511, null)
,(22511, 225111, null)
,(22511, 225112, null)
,(22511, 225113, null)
,(22511, 225114, null)
,(22511, 225115, null)
,(22511, 225116, null)
,(22511, 225117, 2022-10-23)
,(22511, 225118, 2022-11-01)
,(225, 2252, null)
,(2252, 22521, null)
,(22521, 225211, null)
,(22521, 225212, null)
,(22521, 225213, null)
,(22521, 225214, 2022-12-23)
,(22521, 225215, null)
,(22521, 225216, 2022-08-01)
,(22521, 225217, null);
,(22521, 225218, null);

Answer 1

finally I get answer according Recursive sum in tree structure
with C as
(
select
T.RowNo,
T.ID,
T.StartActual,
T.ID as RootID
from MSP.MSPMAIN T
union all
select
T.RowNo,
T.ID,
T.StartActual,
C.RootID
from MSP.MSPMAIN T
inner join C
on T.ID_Parent = C.ID
)
select
T.RowNo,
T.ID,
T.ID_Parent,
T.StartActual,
S.MINeveryNode
from MSP.MSPMAIN T
inner join (
select RootID,
MIN(StartActual) as MINeveryNode
from C
group by RootID
) as S
on T.Id = S.RootID
order by T.RowNo
option (maxrecursion 0)