HOW MANY COUNTRIES DO NOT HAVE AN ROLLER COASTER LONGER THAN 3000?
select count ( * ) from country where country_id not in ( select country_id from roller_coaster where length > 3000 )
WHICH COUNTRY HAVE A ROLLER COASTER LONGER THAN 5000
select t2.name from roller_coaster as t1 join country as t2 on t1.country_id = t2.country_id where t1.length > 5000
WHAT IS THE HIGHEST LENGTH OF ROLL COASTER
select max ( length ) from roller_coaster
WHICH PARK HAS HIGHEST SPEED OF ROLL COASTER
select park from roller_coaster order by speed desc limit 1