--First Exercise
SELECT maxtemperaturef, city
FROM weather, stations
GROUP BY maxtemperaturef, city
ORDER BY maxtemperaturef DESC;
--Second Exercise
SELECT start_station,
    COUNT(*) as trips_count
FROM trips
GROUP BY start_station;
--Third Exercise
SELECT trip_id, duration
FROM trips
GROUP BY trip_id, duration
ORDER BY duration ASC;
--Fourth Exercise
SELECT end_station,
    AVG(duration) as avg_trip
FROM trips
GROUP BY end_station
ORDER BY end_station;