-- ADD COLUMNS
ALTER TABLE result
  ADD (dif_date number(1),
       dif_km number(1),
       dif_price number(1),
       dif_tech number(1),
       dif_desc number(1),
       dif_eqpm number(1),
       dif_sllr number(1),
       dif_extr number(1)
       );
       
       ALTER TABLE result
  ADD (inserted_date date,
       updated_date date);

-- DROP COLUMNS       
--alter table result drop (diff_price, diff_date, diff_km, diff_tech, diff_desc, diff_eqpm, diff_sllr, diff_extr);