(SELECT d.carid
              FROM cars d,
                   (SELECT * FROM carlinks WHERE carlinktypeid = 1) l
             WHERE d.carid = l.carid(+)
               AND (TRUNC(SYSDATE) BETWEEN NVL(l.actualdate, getMinDate)
                                       AND NVL(l.expiredate, getMaxDate))
            START WITH d.carid in nvl(:CarId, <тут должны быть все carid >) 
            CONNECT BY (PRIOR d.carid = l.parentcarid)

SELECT d.depid
              FROM departments d,
                   (SELECT * FROM deplinks WHERE deplinktypeid = 1) l
             WHERE d.depid = l.depid(+)
               AND (TRUNC(SYSDATE) BETWEEN NVL(l.actualdate, getMinDate)
                                       AND NVL(l.expiredate, getMaxDate))
            START WITH nvl(:DepId, -1) in (-1,d.depid) 
            CONNECT BY (PRIOR d.depid = l.parentdepid)