Finding Top level parent of each row of a table [SQL Server 2008]

Question

I have following two tables

Table Person

Id   Name
   1    A
   2    B
   3    C
   4    D
   5    E

Table RelationHierarchy

Answer 1

You could try to use a loop. As you will get many levels of recursion with your approach:

declare @child int = 0
declare @parent int = 1 --child to search
while @child <> @parent 
BEGIN
set @child = @parent
select  @parent = Parentid from @parentchild  where ChildID = @child
END
select @parent