Я думаю, что вы хотите агрегации:
select vehicle_no, division,
max(entry_station) as entry_station,
max(entry_event) as entry_event,
max(entry_leg_no) as entry_leg_no,
max(exit_station) as exit_station,
max(exit_event) as exit_event,
max(exit_leg_no) as exit_leg_no
from t
group by vehicle_no, division