array_sum

This page explains how to use the array_sum function in APL.

The array_sum function in APL computes the sum of all numerical elements in an array. This function is particularly useful when you want to aggregate numerical values stored in an array field, such as durations, counts, or measurements, across events or records. Use array_sum when your dataset includes array-type fields, and you need to quickly compute their total.

For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.

Splunk SPL users

In Splunk SPL, you might need to use commands or functions such as mvsum for similar operations. In APL, array_sum provides a direct method to compute the sum of numerical arrays.

Splunk example

| eval total_duration = mvsum(duration_array)

ANSI SQL users

ANSI SQL does not natively support array operations like summing array elements. However, you can achieve similar results with UNNEST and SUM. In APL, array_sum simplifies this by handling array summation directly.

SQL example

SELECT SUM(value) AS total_duration
FROM UNNEST(duration_array) AS value;

Usage

Syntax

array_sum(array_expression)

Parameters

Parameter	Type	Description
array_expression	array	An array of numerical values to be summed.

Returns

The function returns the sum of all numerical values in the array. If the array is empty or contains no numerical values, the result is null.

Use case example

Summing the duration of all events in an array field.

Query

['otel-demo-traces']
| summarize event_duration = make_list(duration) by ['service.name']
| extend total_event_duration = array_sum(event_duration)

Run in Playground

Output

service.name	total_event_duration
frontend	1667269530000
checkoutservice	3801404276900

The query calculates the total duration of all events for each service.

List of related functions

• array_rotate_right: Rotates array elements to the right by a specified number of positions.
• array_reverse: Reverses the order of array elements.
• array_shift_left: Shifts array elements one position to the left, moving the first element to the last position.