What are name of all the roller coasters?
select name from roller_coaster
Give me their height.
select name,height from roller_coaster
Which one is the highest?
select name,height from roller_coaster order by height desc limit 1
Show me the name and population of the country that has it.
select t1.name, t1.population from country as t1 join roller_coaster as t2 on t1.country_id = t2.country_id order by t2.height desc limit 1