---
title: group() function
description: group() regroups input data by modifying group key of input tables.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/group/
estimated_tokens: 3504
product: Flux
version: v0
---

# group() function

-   Flux 0.7.0+
-   View InfluxDB support

`group()` regroups input data by modifying group key of input tables.

**Note**: Group does not guarantee sort order. To ensure data is sorted correctly, use `sort()` after `group()`.

##### Function type signature

```js
(<-tables: stream[A], ?columns: [string], ?mode: string) => stream[A] where A: Record
```

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

## Parameters

### columns

List of columns to use in the grouping operation. Default is `[]`.

**Note**: When `columns` is set to an empty array, `group()` ungroups all data merges it into a single output table.

### mode

Grouping mode. Default is `by`.

**Available modes**:

-   **by**: Group by columns defined in the `columns` parameter.
-   **except**: Group by all columns *except* those in defined in the `columns` parameter.

### tables

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

## Examples

-   [Group by specific columns](#group-by-specific-columns)
-   [Group by everything except time](#group-by-everything-except-time)
-   [Ungroup data](#ungroup-data)

### Group by specific columns

```js
import "sampledata"

sampledata.int()
    |> group(columns: ["_time", "tag"])
```

[](#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 | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | 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 | 13 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | t2 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:10Z | 10 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:10Z | 4 | t2 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 7 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | -3 | t2 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:30Z | 17 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:30Z | 19 | t2 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 15 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 13 | t2 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:50Z | 4 | t1 |

| *_time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:50Z | 1 | t2 |

### Group by everything except time

```js
import "sampledata"

sampledata.int()
    |> group(columns: ["_time"], mode: "except")
```

[](#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 | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | 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 | 13 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | -3 | t2 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:50Z | 1 | t2 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:10Z | 4 | t2 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 7 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:10Z | 10 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 13 | t2 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:40Z | 15 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:30Z | 17 | t1 |

| _time | *_value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |

### Ungroup data

```js
import "sampledata"

// Merge all tables into a single table
sampledata.int()
    |> group()
```

[](#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 | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | 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 | 13 | 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 | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |
| 2021-01-01T00:00:00Z | 19 | 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 | 13 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Related

-   [Data model - Restructure tables](/flux/v0/get-started/data-model/#restructure-tables)
-   [Group data in InfluxDB with Flux](/influxdb/v2/query-data/flux/group-data/)
-   [InfluxQL – GROUP BY](/influxdb/v1/query_language/explore-data/#the-group-by-clause)

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