Employee Termination Query

SELECT   pap.employee_number, pap.full_name, pap.start_date hire_date,
         ps.actual_termination_date, ps.leaving_reason
    FROM per_all_assignments_f paf,
         per_periods_of_service ps,
         per_all_people_f pap,
         per_person_types ppt
   WHERE paf.period_of_service_id = ps.period_of_service_id
     AND ps.actual_termination_date IS NOT NULL
     AND pap.person_id = paf.person_id
     AND pap.person_type_id = ppt.person_type_id
     AND ps.actual_termination_date BETWEEN pap.effective_start_date
                                        AND pap.effective_end_date
     AND ps.actual_termination_date BETWEEN paf.effective_start_date
                                        AND paf.effective_end_date
     AND ps.actual_termination_date >= &Termination_date
     AND ps.leaving_reason = &reason
ORDER BY pap.employee_number, ps.actual_termination_date