create table objects (
object_id int,
left         int,
right        int,
level        int,
primary key (object_id)
);

SELECT p1.object_id as ObjectID, p2.object_id as PID, p1.name as Name,p2.name as ParentName, 
FROM objects as p1, objects as p2
where p1.left >p2.left and p1.left<p2.right  and (p1.level - p2.level)= 1  

SELECT p1.object_id as ObjectID, p2.object_id as PID, p3.object_id as TopPID, p1.name as Name,p2.name as ParentName, 
FROM objects as p1, objects as p2, objects as p3
where p1.left >p2.left and p1.left<p2.right  and (p1.level - p2.level)= 1  
and p2.left >p3.left and p2.left<p3.right  and p3.level= 1