tree creation UL and LI

i have come across in the need of the code written on the URL below

http://snipplr.com/view/22864

i can integrate this code to my database and it works only for this query

 SELECT * FROM users

it means it displays the tree of the Top Most Root only, But i don't have any idea what should be the sql query if i want to display the tree of a d开发者_Go百科esired user in the database. :-(

please help me.

my table is

users
------
id
name
my_node_id
my_root_id
my_left_node
my_right_node