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
2021-01-01T00:00:00Z 1.2
2021-01-01T02:00:00Z
2021-01-01T03:00:00Z 2.5
2021-01-01T04:00:00Z
The example above returns:
_time _value
2021-01-01T00:00:00Z 1.2
2021-01-01T03:00:00Z 2.5

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:
a b c d
1 2 3 four
5 6

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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.

Flux is going into maintenance mode and will not be supported in InfluxDB 3.0. This was a decision based on the broad demand for SQL and the continued growth and adoption of InfluxQL. We are continuing to support Flux for users in 1.x and 2.x so you can continue using it with no changes to your code. If you are interested in transitioning to InfluxDB 3.0 and want to future-proof your code, we suggest using InfluxQL.

For information about the future of Flux, see the following: