What is the mean number of played when there are less than 18 points and the position is less than 8?
CREATE TABLE "campeonato_paulista" (
  "position" real,
  "team" text,
  "points" real,
  "played" real,
  "drawn" real,
  "lost" real,
  "against" real,
  "difference" text
);
SELECT AVG("played") FROM "campeonato_paulista" WHERE "points"<18 AND "position"<8;