endofday
This page explains how to use the endofday function in APL.
Use the endofday function in APL to calculate the end of the day for a given datetime value. The function returns a datetime set to the last moment of the day (23:59:59.9999999), with an optional offset to shift forward or backward by a specified number of days.
You can use endofday to create daily time boundaries for aggregation, reporting, and filtering. This is especially useful when you need to bucket events into daily intervals or determine how much time remains until the end of a given day.
Use it when you want to:
- Define end-of-day boundaries for daily reports and dashboards.
- Aggregate events up to the end of each day.
- Calculate the remaining time in a day for each event.
Usage
Syntax
endofday(datetime [, offset])Parameters
| Name | Type | Description |
|---|---|---|
| datetime | datetime | The input datetime value. |
| offset | long | Optional: The number of days to offset from the input date. Use negative values for past dates and positive values for future dates. Default is 0. |
Returns
A datetime representing the end of the day (23:59:59.9999999) for the given date, shifted by the offset if specified.
Use case examples
Calculate how far each request is from the end of the day to understand the distribution of traffic within daily windows.
Query
['sample-http-logs']
| extend end = endofday(_time)
| extend remaining_ms = datetime_diff('millisecond', end, _time)
| project _time, end, remaining_ms, methodOutput
| _time | end | remaining_ms | method |
|---|---|---|---|
| 2024-11-14T10:22:31Z | 2024-11-14T23:59:59.9999999Z | 49048000 | GET |
| 2024-11-14T18:45:12Z | 2024-11-14T23:59:59.9999999Z | 18888000 | POST |
| 2024-11-14T23:01:44Z | 2024-11-14T23:59:59.9999999Z | 3496000 | GET |
This query computes the time remaining until the end of the day for each request, useful for understanding traffic distribution across daily windows.
Aggregate trace counts to end-of-day boundaries for each service to create daily summaries.
Query
['otel-demo-traces']
| extend day_end = endofday(_time)
| summarize trace_count = count() by day_end, ['service.name']
| sort by day_end ascOutput
| day_end | service.name | trace_count |
|---|---|---|
| 2024-11-14T23:59:59.9999999Z | frontend | 1523 |
| 2024-11-15T23:59:59.9999999Z | frontend | 1487 |
| 2024-11-16T23:59:59.9999999Z | frontend | 1601 |
This query groups traces by end-of-day boundaries for each service, giving you a daily count of trace activity.
Count error requests grouped by end-of-day boundaries to track daily error volumes.
Query
['sample-http-logs']
| where toint(status) >= 400
| extend day_end = endofday(_time)
| summarize error_count = count() by day_end
| sort by day_end ascOutput
| day_end | error_count |
|---|---|
| 2024-11-14T23:59:59.9999999Z | 67 |
| 2024-11-15T23:59:59.9999999Z | 43 |
| 2024-11-16T23:59:59.9999999Z | 89 |
This query counts HTTP errors by end-of-day boundaries, helping you monitor daily error trends and detect spikes.
List of related functions
- startofday: Returns the start of the day for a datetime, useful for defining the beginning of daily intervals.
- endofweek: Returns the end of the week for a datetime.
- endofmonth: Returns the end of the month for a datetime.
- endofyear: Returns the end of the year for a datetime.
- now: Returns the current datetime, useful for calculating time until end of day.