Your Query Exercise was to find the best time to do database maintenance by querying the Users table, looking for a one-hour window with the lowest number of created users. We kept this one pretty simple by looking at the data in just one table, and we didn’t hassle with time zones. We just wanted the 3 lowest-load hours, in this format:
Mondays, 1:00-1:59 Saturdays, 23:00-23:59 Sundays, 2:00-2:59
The comments on this one were wild! Lots of different approaches, but they all boiled down to two basic styles.
The easy (but not necessarily right) way:
group by date_part