SQL Statement

Hi All

Working in OPM Version : 12.1.3

In this query the problem in case condition,

basically this query list only those employees whose supervisor is attached, it is working fine, but now i want show all employees under my number which is mentioned 661 in case condition.

Please i need some help

SELECT employee_number

   ,employee_name

   ,manager

 FROM ( 

SELECT ppf.full_name employee_name

   ,ppf.employee_number

   ,(SELECT full_name FROM per_all_people_f mgr WHERE mgr.person_id = paf.supervisor_id AND SYSDATE BETWEEN mgr.effective_start_date AND mgr.effective_end_date) manager

 FROM per_all_people_f ppf