SELECT papf.person_number,
papf.full_name,
paaf.assignment_number,
hou.name department
FROM per_all_people_f papf,
per_all_assignments_f paaf,
hr_all_organization_units hou
WHERE papf.person_id = paaf.person_id
AND paaf.organization_id = hou.organization_id
AND SYSDATE BETWEEN papf.effective_start_date
AND papf.effective_end_date
AND SYSDATE BETWEEN paaf.effective_start_date
AND paaf.effective_end_date;