CREATE TABLE table_204_320 (id NUMBER, "rank" NUMBER, "nation" CLOB, "gold" NUMBER, "silver" NUMBER, "bronze" NUMBER, "total" NUMBER)

how many more total medals did china win over japan ?
SELECT (SELECT "total" FROM table_204_320 WHERE "nation" = 'china') - (SELECT "total" FROM table_204_320 WHERE "nation" = 'japan')
SELECT (SELECT "total" FROM "table_204_320" WHERE "nation" = 'china') - (SELECT "total" FROM "table_204_320" WHERE "nation" = 'japan')