Extract Day of Month From Timestamp

Get the day of month from a timestamp using the time:dayOfMonth() function

Query

flowchart LR; %%{init: {"flowchart": {"defaultRenderer": "elk"}} }%% repo{{Events}} 1["Expression"] result{{Result Set}} repo --> 1 1 --> result
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time:dayOfMonth(timestamp, as=day)

Introduction

The time:dayOfMonth() function can be used to extract the day of the month (1-31) from a timestamp field. It returns the day as an integer value representing the date within the month.

In this example, the time:dayOfMonth() function is used to extract the day from a specific timestamp 2025-08-27 08:51:51.000, demonstrating how to get the day value from a datetime.

Step-by-Step

  1. Starting with the source repository events.

  2. flowchart LR; %%{init: {"flowchart": {"defaultRenderer": "elk"}} }%% repo{{Events}} 1["Expression"] result{{Result Set}} repo --> 1 1 --> result style 1 fill:#ff0000,stroke-width:4px,stroke:#000;
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    time:dayOfMonth(timestamp, as=day)

    Extracts the day of the month from the @timestamp field and returns the result in a new field named day. If the as parameter is not specified, the result is returned in a field named _dayOfMonth as default.

  3. Event Result set.

Summary and Results

The query is used to extract the day of the month from a timestamp, which is useful for analyzing event patterns across different days within months.

This query is useful, for example, to analyze daily patterns, group events by day, or identify activity trends within months.

Sample output from the incoming example data:

@timestampday
2025-08-27 08:51:51.00027

The result shows how the time:dayOfMonth() function extracts the day of the month (in this case 27) from the timestamp, returning it as an integer value.

For visualizing this data, consider using a Bar Chart widget to show event counts by day of month, or a Heat Map widget to display activity patterns across days. The time:dayOfMonth() function is often used with other time functions like time:month() and time:year() for complete date analysis.