Another SQL question

Try doing this:

create view temp_cars (year, car, color, car_count) as   select year, car, color, 0
    from yr_model, cars
   where year=94
  union
  select year, car, color, 1
    from inventory
   where year=94;
select year, car, color, sum(car_count)
  from temp_cars
 group by year, car, color;
drop view temp_cars;

OR in Oracle 7.2 and beyond:
select year, car, color, sum(car_count)
  from (select year, car, color, 0 car_count

          from yr_model, cars
         where year=94
        union
        select year, car, color, 1
          from inventory
         where year=94)