What is the Average Qualifying Goals for Jack Froggatt where the Final Goals is greater than 0?
CREATE TABLE "brazil_1950" (
  "player" text,
  "club" text,
  "qualifying_goals" real,
  "finals_goals" real,
  "total_goals" real
);
SELECT AVG("qualifying_goals") FROM "brazil_1950" WHERE "player"='jack froggatt' AND "finals_goals">0;