What is the number of silver medals when there are more than 1 gold, and more than 6 bronze?
CREATE TABLE "world_championships_total_medals" (
  "rank" text,
  "nation" text,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real
);
SELECT MIN("silver") FROM "world_championships_total_medals" WHERE "gold">1 AND "bronze">6;