Gaps & Islands SQL interview questions
Gaps-and-islands problems find consecutive runs (streaks) or split activity into sessions. The trick is a value that stays constant within a run, such as date minus ROW_NUMBER.
- Riders with 3-Day Ride StreaksGaps & Islands · Window Functionshard
- Sessionize Events with a 30-Minute GapWindow Functions · Gaps & Islandshard