Filter a Half-Open Timestamp Window
Return events in the half-open interval from 2024-12-01 00:00:00 inclusive to 2025-01-01 00:00:00 exclusive.
- Date analysis
- Filtering
- Sorting
Exercise brief
Understand the request
Data platform engineer A monthly event export must include every December event without double-counting the next period boundary.
A monthly event export must include every December event without double-counting the next period boundary. Return events in the half-open interval from 2024-12-01 00:00:00 inclusive to 2025-01-01 00:00:00 exclusive.
Return
- Return event_id, event_timestamp, and event_type.
- Order by event_timestamp and event_id.
Constraints
- Filter event_timestamp directly with >= and < predicates.
- Do not wrap event_timestamp in a formatting or date function.
- Order by event_timestamp, then event_id.
Data you will use
Review the relevant tables before deciding how to join, filter, or aggregate them.
temporal_events
event_idINTEGERevent_timestampDATETIMEevent_typeTEXT
Hints, when you need them
Open one clue at a time so you still do the reasoning.
Hint 1
A half-open interval includes its start but excludes its end.
Hint 2
Use separate >= and < predicates on the raw timestamp column.
Hint 3
The exclusive next-period boundary safely includes fractional seconds from the final day.
Verified SQL answer
Attempt the problem first, then compare structure and reasoning—not just syntax.
Reveal solution and explanation
SELECT event_id, event_timestamp, event_type FROM temporal_events WHERE event_timestamp >= '2024-12-01 00:00:00' AND event_timestamp < '2025-01-01 00:00:00' ORDER BY event_timestamp, event_id;Why this works
Half-open ranges compose cleanly: the end of one period is the start of the next, so no timestamp is counted twice. Direct range predicates also preserve index-friendly access.
Success check
Start-boundary and fractional-second events are included, while the exact next-period boundary and NULL timestamp are excluded.
Expected result
Use this output to verify values, aliases, ordering, and row count.
| event_id | event_timestamp | event_type |
|---|---|---|
| 2 | 2024-12-01 00:00:00 | period_start |
| 7 | 2024-12-01 12:00:00 | same_day |
| 3 | 2024-12-15 09:30:00 | mid_period |
| 4 | 2024-12-31 23:59:59 | period_end |
| 8 | 2024-12-31 23:59:59.999 | fractional_end |
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