CREATE TABLE table_204_311 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

which nation had as many silver medals as mexico and turkey combined ?
SELECT "nation" FROM table_204_311 WHERE "silver" = (SELECT SUM("silver") FROM table_204_311 WHERE "nation" IN ('mexico', 'turkey'))
SELECT "nation" FROM "table_204_311" WHERE "silver" = (SELECT SUM("silver") FROM "table_204_311" WHERE "nation" IN ('mexico', 'turkey'))