fill() function

fill() function

The fill() function replaces all null values in an input stream with a non-null value. The output stream is the same as the input stream with all null values replaced in the specified column.

*Function type: Transformation*

fill(column: "_value", value: 0.0)
// OR
fill(column: "_value", usePrevious: true)

Parameters

column

The column in which to replace null values. Defaults to "_value".

*Data type: String*

value

The constant value to use in place of nulls. The value type must match the value type of the column.

usePrevious

When true, assigns the value set in the previous non-null row.

Cannot be used with value.

*Data type: Boolean*

Examples

Fill null values with a specified non-null value

from(bucket: "example-bucket")
  |> range(start: -1h)
  |> filter(fn: (r) =>
    r._measurement == "cpu" and
    r.cpu == "cpu-total"
  )
  |> fill(value: 0.0)

Fill null values with the previous non-null value

from(bucket: "example-bucket")
  |> range(start: -1h)
  |> filter(fn: (r) =>
    r._measurement == "cpu" and
    r.cpu == "cpu-total"
  )
  |> fill(usePrevious: true)

fill