How many sets lost have a sets won less than 0?
CREATE TABLE "statistics" (
  "player" text,
  "played" real,
  "sets_won" real,
  "sets_lost" real,
  "legs_won" real,
  "legs_lost" real,
  "100" real,
  "140" real,
  "180s" real,
  "high_checkout" real,
  "3_dart_average" real
);
SELECT COUNT("sets_lost") FROM "statistics" WHERE "sets_won"<0;