Code Academy really has to do a better job with explaining examples, step by step. This is NOT helpful for beginners.
thanks a lot for your explanation, I was stuck with “f.id < flights.id”, I didn’t understand why we have to compare them.
this course should be improved a bit of explanation
Add an ORDER BY clause to the end of your query – it may make it easier to understand what’s going on when looking at the output table. For the initial query that selects ‘carrier’ add:
ORDER BY carrier, flight_sequence_number;
Use ‘origin’ instead of ‘carrier’ for the next query.
This will show the flight sequence, in order, for each airport – a much better visualization of the result.
try this query…this would make more sense for all of you…
SELECT carrier, id, (SELECT COUNT(*) FROM flights f WHERE f.id < flights.id AND f.carrier=flights.carrier) + 1 AS flight_sequence_number FROM flights order by 1,3 desc;