Query for Hierarchy Path from child to parent for a given child key by user

Question

CREATE TABLE EMP_ID
  HEAD_ID  NUMBER(4),
  TAIL_ID  NUMBER(4),
  NAME     VARCHAR2(20 )
Insert into EMP_ID  Values  (1011, 1008, 'C11');
Insert into EMP_ID  Values  (1008, 1003, 'C8');
Insert into EMP_ID  Values  (1012, 1003, 'C12');
Insert into EMP_ID  Values  (1020, 1003, 'C20');
Insert into EMP_ID  Values  (1025, 1003, 'C25');
Insert into EMP_ID  Values  (1015, 1012, 'C15');
Insert into EMP_ID  Values  (1012, 1005, 'C12');
Insert into EMP_ID  Values  (1005, 1017, 'C5');
COMMIT;now my requirement is like this
if choose the head_id as 1012 and tail_id as 1017
it should traverse the path form tail to head and print the path as shown below
c12/c5/c17/c12such that it shows that tail_id has been used as head_id in the same hierarchy path previously.
here the hierarchy is as shown below
1015
      1012
            1005
                1017

Answer 1

Rede,
Is this what you want?
CREATE TABLE EMP_ID
  HEAD_ID  NUMBER(4),
  TAIL_ID  NUMBER(4),
  NAME     VARCHAR2(20 )
Insert into EMP_ID  Values  (1011, 1008, 'C11');
Insert into EMP_ID  Values  (1008, 1003, 'C8');
Insert into EMP_ID  Values  (1012, 1003, 'C12');
Insert into EMP_ID  Values  (1020, 1003, 'C20');
Insert into EMP_ID  Values  (1025, 1003, 'C25');
Insert into EMP_ID  Values  (1015, 1012, 'C15');
Insert into EMP_ID  Values  (1012, 1005, 'C12');
Insert into EMP_ID  Values  (1005, 1017, 'C5');
Insert into EMP_ID  Values  (1017, 1012, 'C17');  ---- ==== This was missing in your setup example
COMMIT;QUERY and OUTPUT
SELECT *
  FROM (
select
  connect_by_iscycle as CYC
,dt.head_id
,dt.tail_id                     
,sys_connect_by_path
                  (  dt.name
                  ) AS EMP_PATH                   
from   emp_id dt
start with dt.head_id = 1012
connect by  NOCYCLE  dt.head_id= prior dt.tail_id)
CYC     HEAD_ID     TAIL_ID     EMP_PATH
0     1012     1003     /C12
0     1012     1005     /C12
0     1005     1017     /C12/C5
1     1017     1012     /C12/C5/C17
0     1012     1003     /C12/C5/C17/C12If you just want the PATH printed
SELECT *
  FROM (
select     
max(sys_connect_by_path
                  (  dt.name
                  )) AS EMP_PATH                   
from   emp_id dt
start with dt.head_id = 1012
connect by  NOCYCLE  dt.head_id= prior dt.tail_id)
/C12/C5/C17/C12vr,
Sudhakar B.