Getting the parenet id along with the child ids in hierarchy query results

Question

create table test_test2 (do_id_tp varchar2(32),do_id number ,do_up_tp varchar2(32),do_up_id number)
insert into test_test2 values('A_S',100170,'A_S',100001);
insert into test_test2 values('A_S',1001054,'A_S',100001);
insert into test_test2 values('A_S',1001055,'A_S',100001);
insert into test_test2 values('A_S',1001053,'A_S',100001);
insert into test_test2 values('A_S',1001056,'A_S',100001);
insert into test_test2 values('A_S',1001051,'A_S',100001);
insert into test_test2 values('A_S',1001052,'A_S',100001);
insert into test_test2 values('A_S',100358,'A_S',100170);
insert into test_test2 values('A_S',100359,'A_S',100170);
insert into test_test2 values('A_S',100441,'A_S',100170);
insert into test_test2 values('A_S',1001047,'A_S',100441);
9/code]
Upon executing the following query , i'm getting the childs of 100001 and the childs of childs of 100001 etc..
That if fine .But in the output i'm not getting the parent id i.e; 100001 (which is in the where condition)
How to get the parenet id along with the childs id.( without writing the UNION select 100001 from dual)SELECT do_id
FROM (
SELECT d.do_id, d.do_up_id
FROM test_test2 d
WHERE d.do_up_tp = 'A_S' ) m
CONNECT BY NOCYCLE PRIOR m.do_id = m.do_up_id
START WITH m.do_up_id =100001
Edited by: smile on Jan 12, 2012 6:50 PM

Answer 1

If you wish the root parent as a column in your select, you can use CONNECT_BY_ROOT:
SELECT
connect_by_root(do_up_id) root,
do_up_id parent,
do_id
FROM (
   SELECT  d.do_id, d.do_up_id
   FROM test_test2 d
   WHERE    d.do_up_tp = 'A_S'
) m
CONNECT BY NOCYCLE PRIOR m.do_id = m.do_up_id
START WITH m.do_up_id =100001;But if you really wish an extra row in your output with 100001, then your problem is that you do not have a record in your data with do_id = 100001.
Then you either need such a record in your data, or you need to create such a row with for example union all - something like this:
SELECT
do_id
FROM (
   SELECT  d.do_id, d.do_up_id
   FROM test_test2 d
   WHERE    d.do_up_tp = 'A_S'
   UNION ALL
   SELECT 100001 do_id, NULL do_up_id
   FROM DUAL
) m
CONNECT BY NOCYCLE PRIOR m.do_id = m.do_up_id
START WITH m.do_up_id IS NULL;