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maxif aggregation in APL

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Introduction

The maxif aggregation function in APL is useful when you want to return the maximum value from a dataset based on a conditional expression. This allows you to filter the dataset dynamically and only return the maximum for rows that satisfy the given condition. It’s particularly helpful for scenarios where you want to find the highest value of a specific metric, like response time or duration, but only for a subset of the data (e.g., successful responses, specific users, or requests from a particular geographic location).

You can use the maxif function when analyzing logs, monitoring system traces, or inspecting security-related data to get insights into the maximum value under certain conditions.

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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.

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Usage

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Syntax

summarize maxif(column, condition)

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Parameters

• column: The column containing the values to aggregate.
• condition: The condition that must be true for the values to be considered in the aggregation.

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Returns

The maximum value from column for rows that meet the condition. If no rows match the condition, it returns null.

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Use case examples

• Log analysis
• OpenTelemetry traces
• Security logs

['sample-http-logs']
| summarize maxif(req_duration_ms, status == "200")

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List of related aggregations

• minif: Returns the minimum value from a column for rows that satisfy a condition. Use minif when you’re interested in the lowest value under specific conditions.
• max: Returns the maximum value from a column without filtering. Use max when you want the highest value across the entire dataset without conditions.
• sumif: Returns the sum of values for rows that satisfy a condition. Use sumif when you want the total value of a column under specific conditions.
• avgif: Returns the average of values for rows that satisfy a condition. Use avgif when you want to calculate the mean value based on a filter.
• countif: Returns the count of rows that satisfy a condition. Use countif when you want to count occurrences that meet certain criteria.