Documentation

Work with null types

The null type represents a missing or unknown value.

Type name: null

Null syntax

Null types exist in columns of other basic types. Flux does not provide a literal syntax for a null value, however, you can use debug.null() to return a null value of a specified type.

import "internal/debug"

// Return a null string
debug.null(type: "string")

// Return a null integer
debug.null(type: "int")

// Return a null boolean
debug.null(type: "bool")

An empty string ("") is not a null value.

Check if a column value is null

In functions that iterate over rows (such as filter() or map()), use the exists logical operator to check if a column value is null.

Filter out rows with null values
data
    |> filter(fn: (r) => exists r._value)
Given the following input data:
_time_value
2021-01-01T00:00:00Z1.2
2021-01-01T02:00:00Z
2021-01-01T03:00:00Z2.5
2021-01-01T04:00:00Z
The example above returns:
_time_value
2021-01-01T00:00:00Z1.2
2021-01-01T03:00:00Z2.5

Include null values in an ad hoc stream of tables

  1. Use array.from() to create an ad hoc stream of tables.
  2. Use debug.null() to include null column values.
import "array"
import "internal/debug"

array.from(
    rows: [
        {a: 1, b: 2, c: 3, d: "four"},
        {a: debug.null(type: "int"), b: 5, c: 6, d: debug.null(type: "string")}
    ]
)
The example above returns:
abcd
123four
56

Was this page helpful?

Thank you for your feedback!


The future of Flux

Flux is going into maintenance mode. You can continue using it as you currently are without any changes to your code.

Read more

New in InfluxDB 3.4

Key enhancements in InfluxDB 3.4 and the InfluxDB 3 Explorer 1.2.

See the Blog Post

InfluxDB 3.4 is now available for both Core and Enterprise, which introduces offline token generation for use in automated deployments and configurable license type selection that lets you bypass the interactive license prompt. InfluxDB 3 Explorer 1.2 is also available, which includes InfluxDB cache management and other new features.

For more information, check out: