--- title: Aggregate data with InfluxQL description: Use InfluxQL aggregate and selector functions to perform aggregate operations on your time series data. url: https://docs.influxdata.com/influxdb3/cloud-dedicated/query-data/influxql/aggregate-select/ estimated_tokens: 3925 product: InfluxDB Cloud Dedicated version: cloud-dedicated --- # Aggregate data with InfluxQL An InfluxQL query that aggregates data includes the following clauses: \* Required - \* `SELECT`: Specify fields and calculations to output from a measurement or use the wildcard alias (`*`) to select all fields and tags from a measurement. - \* `FROM`: Specify the measurement to query data from. - `WHERE`: Only retrieve data that meets the specified conditions–for example, falls within a time range, contains specific tag values, or contains a field value outside a specified range. - `GROUP BY`: Group data by tag values and time intervals. For simplicity, the term *“aggregate”* in this guide refers to applying both aggregate and selector functions to a dataset. Learn how to apply aggregate operations to your queried data: - [Aggregate and selector functions](#aggregate-and-selector-functions) - [Aggregate functions](#aggregate-functions) - [Selector functions](#selector-functions) - [Example aggregate queries](#example-aggregate-queries) ## Aggregate and selector functions Both aggregate and selector functions return a limited number of rows from each group. Aggregate functions return a single row, whereas some selector functions let you specify the number of rows to return from each group. For example, if you `GROUP BY room` and perform an aggregate operation in your `SELECT` clause, results include an aggregate value for each unique value of `room`. ### Aggregate functions Use **aggregate functions** to aggregate values in a specified field for each group and return a single row per group containing the aggregate field value. [View aggregate functions](/influxdb3/cloud-dedicated/reference/influxql/functions/aggregates/) ##### Basic aggregate query ```sql SELECT MEAN(co) from home ``` ### Selector functions Use **selector functions** to “select” a value from a specified field. [View selector functions](/influxdb3/cloud-dedicated/reference/influxql/functions/selectors/) ##### Basic selector query ```sql SELECT TOP(co, 3) from home ``` ## Example aggregate queries - [Perform an ungrouped aggregation](#perform-an-ungrouped-aggregation) - [Group and aggregate data](#group-and-aggregate-data) - [Downsample data by applying interval-based aggregates](#downsample-data-by-applying-interval-based-aggregates) - [Query rows based on aggregate values](#query-rows-based-on-aggregate-values) #### Sample data The following examples use the sample data written in the [Get started home sensor data](/influxdb3/cloud-dedicated/reference/sample-data/#get-started-home-sensor-data). To run the example queries and return results, [write the sample data](/influxdb3/cloud-dedicated/reference/sample-data/#write-home-sensor-data-to-influxdb) to your InfluxDB Cloud Dedicated database before running the example queries. ### Perform an ungrouped aggregation To aggregate *all* queried values in a specified field: - Use aggregate or selector functions in your `SELECT` statement. - Do not include a `GROUP BY` clause to leave your data ungrouped. ```sql SELECT MEAN(co) AS "average co" FROM home ``` [](#view-example-results) View example results name: home | time | average co | | --- | --- | | 0 | 5.269230769230769 | ### Group and aggregate data To apply aggregate or selector functions to grouped data: - Use aggregate or selector functions in your `SELECT` statement. - Include a `GROUP BY` clause with a comma-delimited list of tags to group by. Keep the following in mind when using `GROUP BY`: - `GROUP BY` can use column aliases that are defined in the `SELECT` clause. ```sql SELECT MEAN(temp) AS "average temp" FROM home GROUP BY room ``` [](#view-example-results) View example results name: home tags: room=Kitchen | time | average temp | | --- | --- | | 0 | 22.623076923076926 | name: home tags: room=Living Room | time | average temp | | --- | --- | | 0 | 22.16923076923077 | #### Downsample data by applying interval-based aggregates A common use case when querying time series is downsampling data by applying aggregates to time-based groups. To group and aggregate data into time-based groups: - In your `SELECT` clause, apply [aggregate](/influxdb3/cloud-dedicated/reference/influxql/functions/aggregates/) or [selector](/influxdb3/cloud-dedicated/reference/influxql/functions/selectors/) functions to queried fields. - In your `WHERE` clause, include time bounds for the query. Interval-based aggregates produce a row for each specified time interval. If no time bounds are specified in the `WHERE` clause, the query uses the default time range (1970-01-01T00:00:00Z to now) and returns a row for each interval in that time range. - In your `GROUP BY` clause: - Use the [`time()` function](/influxdb3/cloud-dedicated/reference/influxql/functions/date-time/#time) to specify the time interval to group by. - *Optional*: Specify other tags to group by. The following example retrieves unique combinations of time intervals and rooms with their minimum, maximum, and average temperatures. ```sql SELECT MAX(temp) AS "max temp", MIN(temp) AS "min temp", MEAN(temp) AS "average temp" FROM home WHERE time >= '2022-01-01T08:00:00Z' AND time < '2022-01-01T20:00:00Z' GROUP BY time(2h), room ``` [](#view-example-results-1) View example results name: home tags: room=Kitchen | time | max temp | min temp | average temp | | --- | --- | --- | --- | | 2022-01-01T08:00:00Z | 23 | 21 | 22 | | 2022-01-01T10:00:00Z | 22.7 | 22.4 | 22.549999999999997 | | 2022-01-01T12:00:00Z | 22.8 | 22.5 | 22.65 | | 2022-01-01T14:00:00Z | 22.8 | 22.7 | 22.75 | | 2022-01-01T16:00:00Z | 22.7 | 22.4 | 22.549999999999997 | | 2022-01-01T18:00:00Z | 23.3 | 23.1 | 23.200000000000003 | | 2022-01-01T20:00:00Z | 22.7 | 22.7 | 22.7 | name: home tags: room=Living Room | time | max temp | min temp | average temp | | --- | --- | --- | --- | | 2022-01-01T08:00:00Z | 21.4 | 21.1 | 21.25 | | 2022-01-01T10:00:00Z | 22.2 | 21.8 | 22 | | 2022-01-01T12:00:00Z | 22.4 | 22.2 | 22.299999999999997 | | 2022-01-01T14:00:00Z | 22.3 | 22.3 | 22.3 | | 2022-01-01T16:00:00Z | 22.6 | 22.4 | 22.5 | | 2022-01-01T18:00:00Z | 22.8 | 22.5 | 22.65 | | 2022-01-01T20:00:00Z | 22.2 | 22.2 | 22.2 | #### Related - [InfluxQL aggregate functions](/influxdb3/cloud-dedicated/reference/influxql/functions/aggregates/) - [InfluxQL selector functions](/influxdb3/cloud-dedicated/reference/influxql/functions/selectors/)