What is the sum of the gold medals of the nation with 4 silvers and more than 6 total medals?
CREATE TABLE "medals_table" (
  "rank" text,
  "nation" text,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real
);
SELECT SUM("gold") FROM "medals_table" WHERE "silver"=4 AND "total">6;