SQL & PL/SQL

Hi all,

I have a table with a self join, basically an employee is managed by an employee..

Using the following query, i'm able to query the data, giving a kind of hierarchical output, this tells me who manages who...

SELECT LPAD(' ', 5* level) || empno
FROM employee
CONNECT BY prior empno = mgr
START WITH mgr is null;

This produces the following output...

SQL> SELECT LPAD(' ', 5* level) || ep_emp_id
  2  FROM employee_on_project
  3  CONNECT BY prior ep_emp_id = ep_mgr_emp_id
  4  START WITH ep_mgr_emp_id is null;

LPAD('',5*LEVEL)||EP_EMP_ID
----------------------------------------------------------------------------------------------------
     c1
          c2
               c4
               c5
               c6
          c3
     c7

7 rows selected.

My question is, how can I edit the query to output only employees at the top of the hierarchy, i.e. only top managers.

Any idea's guys??

Cheers!