what is the rating when the rank (timeslot) is less than 3 and the rank (night) is less than 8?
CREATE TABLE "u_s_nielsen_ratings" (
  "episode" text,
  "rating" real,
  "share" real,
  "rating_share_18_49" text,
  "viewers_millions" real,
  "rank_timeslot" real,
  "rank_night" real,
  "rank_week" text
);
SELECT SUM("rating") FROM "u_s_nielsen_ratings" WHERE "rank_timeslot"<3 AND "rank_night"<8;