Active Employees in HRMS Oracle R12

SELECT           ppf.first_name,ppf.last_name,ppf.full_name,ppf.employee_number,ppf.person_id
FROM per_all_assignments_f paaf,per_assignment_status_types past, per_all_people_f ppf
WHERE paaf.assignment_status_type_id = past.assignment_status_type_id
AND ppf.person_id=paaf.person_id
AND past.user_status = 'Active Assignment'
AND trunc(sysdate) between paaf.effective_start_date and paaf.effective_end_date;