CREATE TABLE captain (captain_id NUMBER, name CLOB, ship_id NUMBER, age CLOB, class CLOB, rank CLOB)
CREATE TABLE ship (ship_id NUMBER, name CLOB, type CLOB, built_year NUMBER, class CLOB, flag CLOB)

Which flag is most widely used among all ships?
SELECT flag FROM ship GROUP BY flag ORDER BY COUNT(*) DESC LIMIT 1
SELECT "flag" FROM "ship" GROUP BY "flag" ORDER BY COUNT(*) DESC FETCH FIRST 1 ROWS ONLY