---
title: experimental.unique() function
description: experimental.unique() returns all records containing unique values in the _value column.
url: https://docs.influxdata.com/flux/v0/stdlib/experimental/unique/
estimated_tokens: 1329
product: Flux
version: v0
---

# experimental.unique() function

-   Flux 0.112.0+
-   View InfluxDB support

`experimental.unique()` is [subject to change at any time](/flux/v0/stdlib/experimental/#experimental-packages-are-subject-to-change).

`experimental.unique()` returns all records containing unique values in the `_value` column.

`null` is considered a unique value.

#### Function behavior

-   Outputs a single table for each input table.
-   Outputs a single record for each unique value in an input table.
-   Leaves group keys, columns, and values unmodified.
-   Drops empty tables.

##### Function type signature

```js
(<-tables: stream[{A with _value: B}]) => stream[{A with _value: B}]
```

For more information, see [Function type signatures](/flux/v0/function-type-signatures/).

## Parameters

### tables

Input data. Default is piped-forward data (`<-`).

## Examples

### Return rows with unique values in each input table

```js
import "experimental"
import "sampledata"

sampledata.int(includeNull: true)
    |> experimental.unique()
```

[](#view-example-input-and-output)

View example input and output

#### Input data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:10Z |  | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z |  | t1 |
| 2021-01-01T00:00:40Z |  | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z |  | t2 |
| 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:40Z |  | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:10Z |  | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z |  | t2 |
| 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Related

-   [unique() function](/flux/v0/stdlib/universe/unique/)

[transformations](/flux/v0/tags/transformations/) [selectors](/flux/v0/tags/selectors/)