|
| 1 | +--- |
| 2 | +title: avgif |
| 3 | +description: 'This page explains how to use the avgif aggregation function in APL.' |
| 4 | +--- |
| 5 | + |
| 6 | +The `avgif` aggregation function in APL allows you to calculate the average value of a field, but only for records that satisfy a given condition. This function is particularly useful when you need to perform a filtered aggregation, such as finding the average response time for requests that returned a specific status code or filtering by geographic regions. The `avgif` function is highly valuable in scenarios like log analysis, performance monitoring, and anomaly detection, where focusing on subsets of data can provide more accurate insights. |
| 7 | + |
| 8 | +## For users of other query languages |
| 9 | + |
| 10 | +If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL. |
| 11 | + |
| 12 | +<AccordionGroup> |
| 13 | +<Accordion title="Splunk SPL users"> |
| 14 | + |
| 15 | +In Splunk, you achieve similar functionality using the combination of a `stats` function with conditional filtering. In APL, `avgif` provides this filtering inline as part of the aggregation function, which can simplify your queries. |
| 16 | + |
| 17 | +<CodeGroup> |
| 18 | +```sql Splunk example |
| 19 | +| stats avg(req_duration_ms) by id where status = "200" |
| 20 | +``` |
| 21 | + |
| 22 | +```kusto APL equivalent |
| 23 | +['sample-http-logs'] |
| 24 | +| summarize avgif(req_duration_ms, status == "200") by id |
| 25 | +``` |
| 26 | +</CodeGroup> |
| 27 | + |
| 28 | +</Accordion> |
| 29 | +<Accordion title="ANSI SQL users"> |
| 30 | + |
| 31 | +In ANSI SQL, you can use a `CASE` statement inside an `AVG` function to achieve similar behavior. APL simplifies this with `avgif`, allowing you to specify the condition directly. |
| 32 | + |
| 33 | +<CodeGroup> |
| 34 | +```sql SQL example |
| 35 | +SELECT id, AVG(CASE WHEN status = '200' THEN req_duration_ms ELSE NULL END) |
| 36 | +FROM sample_http_logs |
| 37 | +GROUP BY id |
| 38 | +``` |
| 39 | + |
| 40 | +```kusto APL equivalent |
| 41 | +['sample-http-logs'] |
| 42 | +| summarize avgif(req_duration_ms, status == "200") by id |
| 43 | +``` |
| 44 | +</CodeGroup> |
| 45 | + |
| 46 | +</Accordion> |
| 47 | +</AccordionGroup> |
| 48 | + |
| 49 | +## Usage |
| 50 | + |
| 51 | +### Syntax |
| 52 | + |
| 53 | +```kusto |
| 54 | +summarize avgif(expr, predicate) by grouping_field |
| 55 | +``` |
| 56 | + |
| 57 | +### Parameters |
| 58 | + |
| 59 | +- **`expr`**: The field for which you want to calculate the average. |
| 60 | +- **`predicate`**: A boolean condition that filters which records are included in the calculation. |
| 61 | +- **`grouping_field`**: (Optional) A field by which you want to group the results. |
| 62 | + |
| 63 | +### Returns |
| 64 | + |
| 65 | +The function returns the average of the values from the `expr` field for the records that satisfy the `predicate`. If no records match the condition, the result is `null`. |
| 66 | + |
| 67 | +## Use case examples |
| 68 | + |
| 69 | +<Tabs> |
| 70 | +<Tab title="Log analysis"> |
| 71 | + |
| 72 | +In this example, you calculate the average request duration for HTTP status 200 in different cities. |
| 73 | + |
| 74 | +**Query** |
| 75 | + |
| 76 | +```kusto |
| 77 | +['sample-http-logs'] |
| 78 | +| summarize avgif(req_duration_ms, status == "200") by ['geo.city'] |
| 79 | +``` |
| 80 | + |
| 81 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B%27sample-http-logs%27%5D%20%7C%20summarize%20avgif%28req_duration_ms%2C%20status%20%3D%3D%20%22200%22%29%20by%20%5B%27geo.city%27%5D%22%7D) |
| 82 | + |
| 83 | +**Output** |
| 84 | + |
| 85 | +| geo.city | avg_req_duration_ms | |
| 86 | +|------------|---------------------| |
| 87 | +| New York | 325 | |
| 88 | +| London | 400 | |
| 89 | +| Tokyo | 275 | |
| 90 | + |
| 91 | +This query calculates the average request duration (`req_duration_ms`) for HTTP requests that returned a status of 200 (`status == "200"`), grouped by the city where the request originated (`geo.city`). |
| 92 | + |
| 93 | +</Tab> |
| 94 | +<Tab title="OpenTelemetry traces"> |
| 95 | + |
| 96 | +In this example, you calculate the average span duration for traces that ended with HTTP status 500. |
| 97 | + |
| 98 | +**Query** |
| 99 | + |
| 100 | +```kusto |
| 101 | +['otel-demo-traces'] |
| 102 | +| summarize avgif(duration, status == "500") by ['service.name'] |
| 103 | +``` |
| 104 | + |
| 105 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B%27otel-demo-traces%27%5D%20%7C%20summarize%20avgif%28duration%2C%20status%20%3D%3D%20%22500%22%29%20by%20%5B%27service.name%27%5D%22%7D) |
| 106 | + |
| 107 | +**Output** |
| 108 | + |
| 109 | +| service.name | avg_duration | |
| 110 | +|-----------------------|--------------| |
| 111 | +| checkoutservice | 500ms | |
| 112 | +| frontend | 600ms | |
| 113 | +| cartservice | 475ms | |
| 114 | + |
| 115 | +This query calculates the average span duration (`duration`) for traces where the status code is 500 (`status == "500"`), grouped by the service name (`service.name`). |
| 116 | + |
| 117 | +</Tab> |
| 118 | +<Tab title="Security logs"> |
| 119 | + |
| 120 | +In this example, you calculate the average request duration for failed HTTP requests (status code 400 or higher) by country. |
| 121 | + |
| 122 | +**Query** |
| 123 | + |
| 124 | +```kusto |
| 125 | +['sample-http-logs'] |
| 126 | +| summarize avgif(req_duration_ms, toint(status) >= 400) by ['geo.country'] |
| 127 | +``` |
| 128 | + |
| 129 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/explorer?initForm=%7B%22apl%22%3A%22%5B%27sample-http-logs%27%5D%20%7C%20summarize%20avgif%28req_duration_ms%2C%20toint%28status%29%20%3E%3D%20400%29%20by%20%5B%27geo.country%27%5D%22%7D) |
| 130 | + |
| 131 | +**Output** |
| 132 | + |
| 133 | +| geo.country | avg_req_duration_ms | |
| 134 | +|---------------|---------------------| |
| 135 | +| USA | 450 | |
| 136 | +| Canada | 500 | |
| 137 | +| Germany | 425 | |
| 138 | + |
| 139 | +This query calculates the average request duration (`req_duration_ms`) for failed HTTP requests (`status >= 400`), grouped by the country of origin (`geo.country`). |
| 140 | + |
| 141 | +</Tab> |
| 142 | +</Tabs> |
| 143 | + |
| 144 | +## List of related aggregations |
| 145 | + |
| 146 | +- [**minif**](/apl/aggregation-function/minif): Returns the minimum value of an expression, filtered by a predicate. Use when you want to find the smallest value for a subset of data. |
| 147 | +- [**maxif**](/apl/aggregation-function/maxif): Returns the maximum value of an expression, filtered by a predicate. Use when you are looking for the largest value within specific conditions. |
| 148 | +- [**countif**](/apl/aggregation-function/countif): Counts the number of records that match a condition. Use when you want to know how many records meet a specific criterion. |
| 149 | +- [**sumif**](/apl/aggregation-function/sumif): Sums the values of a field that match a given condition. Ideal for calculating the total of a subset of data. |
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