what is the least silver for germany when gold is more than 4?
CREATE TABLE "medal_count_by_country" (
  "rank" real,
  "nation" text,
  "gold" real,
  "silver" real,
  "bronze" real,
  "total" real
);
SELECT MIN("silver") FROM "medal_count_by_country" WHERE "nation"='germany' AND "gold">4;