TSQL - While loop within select? - sql-server

Question

In SQL server
Ok, so I'm working with a database table in which rows can have parent rows, which can then have parent rows of their own. I need to select the root 'row'. I don't know the best way to do this.
There is a field called ParentId, which links the row to the row with that ID. When the ParentId = 0, it is the root row.
This is my query now:
SELECT Releases.Name,WorkLog.WorkLogId
FROM WorkLog,Releases
WHERE
Releases.ReleaseId = WorkLog.ReleaseId
and WorkLogDateTime >= #StartDate
and WorkLogDateTime <= #end
I don't really need the Release Name of the child releases, I want only the root Release Name, so I want to select the result of a While loop like this:
WHILE (ParentReleaseId != 0)
BEGIN
#ReleaseId = ParentReleaseId
END
Select Release.Name
where Release.RealeaseId = #ReleaseId
I know that syntax is horrible, but hopefully I'm giving you an idea of what I'm trying to acheive.

Answer 1

Here is an example, which could be usefull:
This query is getting a lower element of a tree, and searching up to the parent of parents.
Like I have 4 level in my table -> category 7->5, 5->3, 3-> 1. If i give it to the 5 it will find the 1, because this is the top level of the three.
(Changing the last select you can have all of the parents up on the way.)
DECLARE #ID int
SET #ID = 5;
WITH CTE_Table_1
(
ID,
Name,
ParentID
)
AS(
SELECT
ID,
Name,
ParentID
FROM Table_1
WHERE ID = #ID
UNION ALL
SELECT
T.ID,
T.Name,
T.ParentID
FROM Table_1 T
INNER JOIN CTE_Table_1 ON CTE_Table_1.ParentID = T.ID
)
SELECT * FROM CTE_Table_1 WHERE ParentID = 0

Answer 2

something like this
with cte as
(
select id,parent_id from t where t.id=#myStartingValue
union all
select t.id,t.parent_id
from cte
join t on cte.parent_id = t.id where cte.parent_id<>0
)
select *
from cte
join t on cte.id=t.id where cte.parent_id = 0
and with fiddle : http://sqlfiddle.com/#!3/a5fa1/1/0

Answer 3

Using Andras approach, I edited the final select to directly give me the ID of the root release
WITH cte_Releases
(
ReleaseId,
ParentReleaseID
)
AS(
SELECT
ReleaseId,
ParentReleaseID
FROM Releases
Where ReleaseId = 905
UNION ALL
SELECT
R.ReleaseId,
R.ParentReleaseID
FROM Releases R
INNER JOIN cte_Releases ON cte_Releases.ParentReleaseID = R.ReleaseId
)
SELECT max(ReleaseId) as ReleaseId, min(ReleaseId) as RootReleaseId FROM cte_Releases
My problem now is I want to run through all #IDs (905 in that code) and join each record to a result