declare @tree table (id int identity, parent int , n varchar( 33 ), le int, ri int)

set nocount on
insert @tree select  0 , 'K', 1 , 16 
insert @tree select  1 , '1', 2 , 13 
insert @tree select  2 , '11', 3 , 4 
insert @tree select  2 , '12', 5 , 12 
insert @tree select  4 , '121', 6 , 7 
insert @tree select  4 , '122', 8 , 9 
insert @tree select  4 , '123', 10 , 11 
insert @tree select  1 , '2', 14 , 15 
   -- посмотреть дерево
 
select t1.le, t1.ri, t1.id, t1.parent,replicate(' ',count(*))+t1.n
  from @tree t1, @tree t2
  where t2.le<=t1.le and t2.ri>=t1.ri
  group by t1.n, t1.le,t1.le, t1.ri, t1.parent,t1.id
  order by t1.le


 -- дети и их родители
 
select t0.id, t.id par, t0.parent 
  from @tree t, @tree t0 
  where t.le<t0.le and t.ri>t0.ri 
    and not exists(select * from @tree t1 
         where t1.le > t.le and t1.le < t0.le
           and t1.ri > t0.ri and t1.ri < t.ri )