Buyer query (link between po_agents and per_all_people_f)

select per.full_name "Buyer Name" ,pa.START_DATE_ACTIVE "Begin Date",pa.END_DATE_ACTIVE "End Date",per.employee_number
from po_agents pa,
     per_all_people_f per
where 1=1
and pa.AGENT_ID = per.person_id
AND SYSDATE between per.effective_start_date AND per.effective_end_date
order by per.employee_number