What cities do students live in?
SELECT DISTINCT city_code FROM Student
SELECT DISTINCT city_code FROM Student
[{'city_code': 'BAL'}, {'city_code': 'HKG'}, {'city_code': 'WAS'}, {'city_code': 'CHI'}, {'city_code': 'YYZ'}, {'city_code': 'PIT'}, {'city_code': 'HOU'}, {'city_code': 'PHL'}, {'city_code': 'DAL'}, {'city_code': 'DET'}, {'city_code': 'LON'}, {'city_code': 'NYC'}, {'city_code': 'LOS'}, {'city_code': 'ROC'}, {'city_code': 'PEK'}, {'city_code': 'SFO'}, {'city_code': 'ATL'}, {'city_code': 'NAR'}, {'city_code': 'BOS'}]