How many students are from each city, and which cities have more than one cities?
SELECT count(*) ,  city_code FROM student GROUP BY city_code HAVING count(*)  >  1
SELECT count(*) ,  city_code FROM student GROUP BY city_code HAVING count(*)  >  1
[{'count(*)': 4, 'city_code': 'BAL'}, {'count(*)': 3, 'city_code': 'HKG'}, {'count(*)': 3, 'city_code': 'NYC'}, {'count(*)': 3, 'city_code': 'PHL'}, {'count(*)': 4, 'city_code': 'PIT'}, {'count(*)': 3, 'city_code': 'WAS'}, {'count(*)': 2, 'city_code': 'YYZ'}]