CREATE TABLE ship (ship_id NUMBER, name CLOB, type CLOB, nationality CLOB, tonnage NUMBER)
CREATE TABLE mission (mission_id NUMBER, ship_id NUMBER, code CLOB, launched_year NUMBER, location CLOB, speed_knots NUMBER, fate CLOB)

What are the nations that have more than two ships?
SELECT nationality FROM ship GROUP BY nationality HAVING COUNT(*) > 2
SELECT "nationality" FROM "ship" GROUP BY "nationality" HAVING COUNT(*) > 2