Who are all the drivers?
select * from drivers
Show the id and number of races of those who have at most participated in 30 races.
select t1.driverid, count(*) from drivers as t1 join results as t2 on t1.driverid = t2.driverid join races as t3 on t2.raceid = t3.raceid group by t1.driverid having count(*) <= 30