Name the average bronze with silver more than 0, total of 6 and gold more than 0
CREATE TABLE "performance_by_nation" (
  "rank" real,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real
);
SELECT AVG("bronze") FROM "performance_by_nation" WHERE "silver">0 AND "total"=6 AND "gold">0;