CREATE TABLE mountain (mountain_id NUMBER, name CLOB, height NUMBER, prominence NUMBER, range CLOB, country CLOB)
CREATE TABLE climber (climber_id NUMBER, name CLOB, country CLOB, time CLOB, points NUMBER, mountain_id NUMBER)

What are the names of countains that no climber has climbed?
SELECT name FROM mountain WHERE NOT mountain_id IN (SELECT mountain_id FROM climber)
SELECT "name" FROM "mountain" WHERE NOT "mountain_id" IN (SELECT "mountain_id" FROM "climber")