What is the lowest value for Sydney, when Perth is less than 169,000, and when NIGHTLY RANK is less than 5?
CREATE TABLE "ratings" (
  "episode_number_production_number" text,
  "title" text,
  "sydney" real,
  "melbourne" real,
  "brisbane" real,
  "adelaide" real,
  "perth" real,
  "total" real,
  "weekly_rank" real,
  "nightly_rank" real
);
SELECT MIN("sydney") FROM "ratings" WHERE "perth"<'169,000' AND "nightly_rank"<5;