CREATE TABLE table_name_30 (bronze NUMBER, silver VARCHAR2, total VARCHAR2, gold VARCHAR2)

Who has a total of the Bronze less than 4, gold more than 0, and no silver?
SELECT SUM(bronze) FROM table_name_30 WHERE total < 4 AND gold > 0 AND silver = 0
SELECT SUM("bronze") FROM "table_name_30" WHERE "gold" > 0 AND "silver" = 0 AND "total" < 4