COLUMN employee_number FORMAT A15
COLUMN employee_name   FORMAT A30
VARIABLE empno VARCHAR2(30)
EXEC :empno := '12345';

SELECT  ppf.employee_number
,       ppf.full_name                           employee_name
,       TO_CHAR(pos.actual_termination_date
        ,       'fmDy MM/DD/YYYY')              term_date
FROM    hr.per_all_people_f             ppf
,       hr.per_all_assignments_f        paf
,       hr.per_periods_of_service       pos
WHERE   ppf.employee_number      = :empno
AND     ppf.person_id            = paf.person_id
AND     TRUNC(SYSDATE) BETWEEN ppf.effective_start_date
                           AND ppf.effective_end_date
AND     paf.assignment_type      = 'E'
AND     paf.effective_start_date = (SELECT MAX(paf2.effective_start_date)
                                    FROM   hr.per_all_assignments_f  paf2
                                    WHERE  paf2.assignment_id   = paf.assignment_id
                                    AND    paf2.assignment_type = paf.assignment_type)
AND     paf.period_of_service_id = pos.period_of_service_id
/