aggregateWindow() function

*Function type: Aggregate*

As data is windowed into separate tables and processed, the _time column is dropped from each group key. This function copies the timestamp from a remaining column into the _time column. View the function definition.

aggregateWindow() restores the original _start and _stop values of input data and, by default, uses _stop to set the _time value for each aggregated window. Each row in the output of aggregateWindow represents an aggregated window ending at _time.

Make sure fn parameter names match each specified parameter. To learn why, see .

The duration of windows.

Calendar months and years

every supports all , including calendar months (1mo) and years ().

fn

The used in the operation.

*Data type: Function*

Only aggregate and selector functions with a column parameter (singular) work with aggregateWindow().

The column on which to operate. Defaults to "_value".

*Data type: String*

timeSrc

The time column from which time is copied for the aggregate record. Defaults to "_stop".

The “time destination” column to which time is copied for the aggregate record. Defaults to "_time".

*Data type: String*

createEmpty

For windows without data, this will create an empty window and fill it with a null aggregate value. Defaults to true.

*Data type: Boolean*

The examples below use a data variable to represent a filtered data set.

data = from(bucket: "example-bucket")
  |> range(start: -1h)
  |> filter(fn: (r) =>
    r._measurement == "mem" and
    r._field == "used_percent")

Use an aggregate function with default parameters

The following example uses the default parameters of the to aggregate time-based windows:

Specify parameters of the aggregate function

data
  |> aggregateWindow(
    every: 5m,
    fn: (column, tables=<-) => tables |> quantile(q: 0.99, column:column)
  )

Window and aggregate by calendar month

aggregateWindow = (every, fn, column="_value", timeSrc="_stop", timeDst="_time", tables=<-) =>
    tables
        |> window(every:every)
        |> fn(column:column)
        |> window(every:inf, timeColumn:timeDst)

Related articles

• InfluxQL – GROUP BY time()