CTE Query Not Returning Desired Results - common-table-expression

Question

I'm not getting the first record below returned in my CTE query (shown later):
Here's my table:
Key ParentID ChildID (Removed DateJoined Field here)
1 0 1
3 1 83
4 1 84
6 83 85
7 85 86
8 83 87
My CTE Query produces the following results:
ID Name Date Joined Parent ID Parent Name Level
83 Hanks, James 2014-09-13 1 Golko, Richard 1
84 Hanks, James 2014-09-13 1 Golko, Richard 1
85 Walker, Jamie 2014-09-13 83 Hanks, James 2
87 Newman, Betty 2014-09-20 83 Hanks, James 2
86 Adams, Ken 2014-09-13 85 Walker, Jamie 3
How can i also return the first record with ParentID = 0?
When I call the following sproc like this:
EXEC UCU_RTG_ProgramStructure_GetMemberTree 0,4
I still only get results starting with parentID=1 as shown above
Here's my CTE Query:
CREATE PROCEDURE [dbo].[UCU_RTG_ProgramStructure_GetMemberTree]
#ParentID int,
#MaxLevel int
AS
WITH matrix
AS
(
--initialization
SELECT UserID, DateJoined, ParentID, 1 AS lvl
FROM dbo.UCU_RTG_ProgramStructure
WHERE ParentID = #ParentID
UNION ALL
--recursive execution
SELECT p.UserID,p.DateJoined,p.ParentID, lvl+1
FROM dbo.UCU_RTG_ProgramStructure p INNER JOIN matrix m
ON p.ParentID = m.UserID
WHERE lvl < #MaxLevel
)
SELECT matrix.UserID, u.LastName + ', ' + u.FirstName AS Member ,DateJoined,ParentID,u2.LastName + ', ' + u2.FirstName AS Parent,lvl
FROM matrix
INNER JOIN dbo.Users u
ON u.UserID = matrix.UserID
INNER JOIN dbo.Users u2
ON u2.UserID = matrix.ParentID
ORDER BY ParentID
THE CTE Query is fine except it doesn't return the parentID=0 record(s)
Thanks...

Answer 1

I figured it out finally after looking at my post to make sure it was correct: the final select clause is wrong:
SELECT matrix.UserID, u.LastName + ', ' + u.FirstName AS Member ,DateJoined,ParentID,u2.LastName + ', ' + u2.FirstName AS Parent,lvl
FROM matrix
INNER JOIN dbo.Users u
ON u.UserID = matrix.UserID
INNER JOIN dbo.Users u2
ON u2.UserID = matrix.ParentID
the last INNER JOIN has to be changed to LEFT JOIN because there is no UserID 0 to join the ParentID 0 to.
Hope this helps someone else with recursive CTE queries.