docs-v2/content/influxdb/v1/flux/guides/fill.md

title	seotitle	list_title	description	weight	menu	list_query_example	canonical	v2
Fill null values in data	Fill null values in data	Fill	Use the `fill()` function to replace _null_ values.	10	influxdb_v1 parent name Query with Flux Fill	fill_null	/influxdb/v2/query-data/flux/fill/	/influxdb/v2/query-data/flux/fill/

Use the fill() function to replace null values with:

• the previous non-null value
• a specified value

data
  |> fill(usePrevious: true)

// OR

data
  |> fill(value: 0.0)

{{% note %}}

Fill empty windows of time

The fill() function does not fill empty windows of time. It only replaces null values in existing data. Filling empty windows of time requires time interpolation (see influxdata/flux#2428). {{% /note %}}

Fill with the previous value

To fill null values with the previous non-null value, set the usePrevious parameter to true.

{{% note %}} Values remain null if there is no previous non-null value in the table. {{% /note %}}

data
  |> fill(usePrevious: true)

{{< flex >}} {{% flex-content %}} Given the following input:

_time	_value
2020-01-01T00:01:00Z	null
2020-01-01T00:02:00Z	0.8
2020-01-01T00:03:00Z	null
2020-01-01T00:04:00Z	null
2020-01-01T00:05:00Z	1.4
{{% /flex-content %}}
{{% flex-content %}}
fill(usePrevious: true) returns:

_time	_value
2020-01-01T00:01:00Z	null
2020-01-01T00:02:00Z	0.8
2020-01-01T00:03:00Z	0.8
2020-01-01T00:04:00Z	0.8
2020-01-01T00:05:00Z	1.4
{{% /flex-content %}}
{{< /flex >}}

Fill with a specified value

To fill null values with a specified value, use the value parameter to specify the fill value. The fill value must match the data type of the column.

data
  |> fill(value: 0.0)

{{< flex >}} {{% flex-content %}} Given the following input:

_time	_value
2020-01-01T00:01:00Z	null
2020-01-01T00:02:00Z	0.8
2020-01-01T00:03:00Z	null
2020-01-01T00:04:00Z	null
2020-01-01T00:05:00Z	1.4
{{% /flex-content %}}
{{% flex-content %}}
fill(value: 0.0) returns:

_time	_value
2020-01-01T00:01:00Z	0.0
2020-01-01T00:02:00Z	0.8
2020-01-01T00:03:00Z	0.0
2020-01-01T00:04:00Z	0.0
2020-01-01T00:05:00Z	1.4
{{% /flex-content %}}
{{< /flex >}}