What is the name of the storm affected the most number of cities?
select t1.name from storm as t1 join affected_region as t2 on t1.storm_id = t2.storm_id group by t1.storm_id order by sum(t2.number_city_affected) desc limit 1;
How about of the storms that affected at least two regions?
select t1.name from storm as t1 join affected_region as t2 on t1.storm_id = t2.storm_id group by t1.storm_id having count(*) >= 2;
Among the result, which one affected at least 10 cities?
select t1.name from storm as t1 join affected_region as t2 on t1.storm_id = t2.storm_id group by t1.storm_id having count(*) >= 2 intersect select t1.name from storm as t1 join affected_region as t2 on t1.storm_id = t2.storm_id group by t1.storm_id having sum(t2.number_city_affected) >= 10;