what is the average points when the goal difference is less than 17, the club is getafe cf and the goals for is more than 30?
CREATE TABLE "final_table" (
  "position" real,
  "club" text,
  "played" real,
  "points" real,
  "wins" real,
  "draws" real,
  "losses" real,
  "goals_for" real,
  "goals_against" real,
  "goal_difference" real
);
SELECT AVG("points") FROM "final_table" WHERE "goal_difference"<17 AND "club"='getafe cf' AND "goals_for">30;