-- Oracle --
WITH rank_table AS
(
SELECT 9981 t_a1, 9997 t_b1, 9011 t_c1 FROM dual
)
SELECT t_a1, t_b1, t_c1
     , GREATEST(t_a1, t_b1, t_c1) t_max
     ,    LEAST(t_a1, t_b1, t_c1) t_min
  FROM rank_table
;