Hey guys, I’m currently working on this topic. I found one thing that disturbs me a lot.
From the example, the line goes:
WHERE f.id < flights.id
AND f.carrier=flights.carrier) + 1
Since the query is for viewing flights by carrier, flight id, and sequence number, I’m not quite understand that why there is a condition when the id is smaller than others? And what is the ‘+1’ means?