Oracle : 11GR2 - Recursive subqueries for hierarchy traversal

Recursive Subquery Example =========================== WITH   reports_to_101 (eid, emp_last, mgr_id, reportLevel) AS   (      SELECT employee_id, last_name, manager_id, 0 reportLevel      FROM employees      WHERE employee_id = 101    UNION ALL      SELECT e.employee_id, e.last_name, e.manager_id, reportLevel+1      FROM reports_to_101 r /* MAGIC IS HERE */          ,employees e      WHERE r.eid = e.manager_id   ) SELECT eid, emp_last, mgr_id, reportLevel FROM reports_to_101 ORDER BY reportLevel, eid;        EID EMP_LAST                      MGR_ID REPORTLEVEL ---------- ------------------------- ---------- -----------        101 Kochhar                          100           0        108 Greenberg                        101           1        200 Whalen                           101           1        203 Mavris                           101           1        204 Baer                             101           1        205 Higgins                          101           1        109 Faviet                           108           2        110 Chen                             108           2        111 Sciarra                          108           2        112 Urman                            108           2        113 Popp                             108           2        206 Gietz                            205           2 Ref