CREATE TABLE table_6284 ("Rank" TEXT, "Institution" TEXT, "Gold" FLOAT, "Silver" FLOAT, "Bronze" FLOAT)

What is the fewest number of silvers for teams with more than 21 gold and more than 4 bronze?
SELECT MIN("Silver") FROM table_6284 WHERE "Bronze" > '4' AND "Gold" > '21'
SELECT MIN("Silver") FROM "table_6284" WHERE "Bronze" > '4' AND "Gold" > '21'