Need to find region and its sub region

Question

Hi,
I have a table levels which has record at any levels.
levels_id region_name region_parent
1 xyz 0
2 xyz1 1
3 xyz2 2
4 xyz3 3
5 xyz11 1
6 xyz12 5
7 xyz21 1
8 xyz22 7
9 **** 100
10 ***1 101
i need to find all the region under levels_id = 1 at any levels
Please help me
regards
shyam

Answer 1

is this what you are after?
with t as
(select 1 levels_id,  'xyz' region_nm,  0 region_parent from dual union
select 2, 'xyz1', 1 from dual union
select 3,'xyz2', 2 from dual union
select 4, 'xyz3', 3 from dual union
select 5, 'xyz11', 1 from dual union
select 6, 'xyz12', 5 from dual union
select 7, 'xyz21', 1 from dual union
select 8, 'xyz22', 7 from dual
select /*levels_id, region_nm, region_parent,  */
substr(sys_connect_by_path(region_nm, '-->'),4)  from t
where connect_by_isleaf = 1
--start with  region_parent = 1
connect by prior region_parent = levels_id
xyz
xyz1-->xyz
xyz2-->xyz1-->xyz
xyz3-->xyz2-->xyz1-->xyz
xyz11-->xyz
xyz12-->xyz11-->xyz
xyz21-->xyz
xyz22-->xyz21-->xyz