How to get Active Users

select fu.user_name, papf.employee_number, papf.full_name, haou.name
  from FND_USER                  fu,
       PER_ALL_PEOPLE_F          papf,
       per_all_assignments_f     paaf,
       HR_ALL_ORGANIZATION_UNITS haou
 where 1 = 1
   and fu.employee_id = papf.person_id
   and sysdate between papf.effective_start_date and  papf.effective_end_date
   and paaf.person_id = papf.person_id and sysdate between paaf.effective_start_date and  paaf.effective_end_date
   and haou.organization_id = paaf.organization_id
   order by 4,1