Could you list all the cities in ascending alphabetical order?
select city from city order by city asc
Which cities were once host cities?
select t3.city from city as t3 join hosting_city as t4 on t3.city_id = t4.host_city
Which cities had a higher temperature in Feb than in Jun or were a host city?
select t1.city from city as t1 join temperature as t2 on t1.city_id = t2.city_id where t2.feb > t2.jun union select t3.city from city as t3 join hosting_city as t4 on t3.city_id = t4.host_city