Hierarchial Structure with Child Parameter

Question

I have a query like this
select child
from t
START WITH parent = 'DIV'
CONNECT BY PRIOR child= parent
when i give some parent value its fetching the entire structure from DIV parent.
i need to restric the rows to some specific leaf. i.e i need a additional parameter called child where i will child value so that it have return only the row from that parent to given child.I dont need other trees.
For eg DIV is parent for A, B ,C
A is parent for D,E
B is parent of F,G,H
C has no child.
If i give parameter DIV is parent and G has child i need only this hierarchy. this should return only two rows
A and G
Please let me know if i am not clear..
Pls Help
VInoth.

Answer 1

Maybe combining the two hierarchies:
SQL> with t as (
  2  select 'A' child, 'DIV' parent from dual union all
  3  select 'B' child, 'DIV' parent from dual union all
  4  select 'C' child, 'DIV' parent from dual union all
  5  select 'D' child, 'A' parent from dual union all
  6  select 'E' child, 'A' parent from dual union all
  7  select 'F' child, 'B' parent from dual union all
  8  select 'G' child, 'B' parent from dual union all
  9  select 'H' child, 'B' parent from dual
10  )
11  select t1.child, t2.lev
12  from (select child from t CONNECT BY prior parent=child start with child='G') t1,
13  (select child, level lev from t CONNECT BY prior child=parent start with parent='DIV') t2
14  where t1.child=t2.child;
CHILD                       LEV
B                             1
G                             2you can add a condition on LEV that is the level in the top-down hierarchy...
But I think this could be slow...
Max