---
title: window() function
description: window() groups records using regular time intervals.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/window/
estimated_tokens: 4990
product: Flux
version: v0
---

# window() function

-   Flux 0.7.0+
-   View InfluxDB support

`window()` groups records using regular time intervals.

The function calculates time windows and stores window bounds in the `_start` and `_stop` columns. `_start` and `_stop` values are assigned to rows based on the row’s `_time` value.

A single input row may be placed into zero or more output tables depending on the parameters passed into `window()`.

This function is intended to be used when `timeColumn` (`_time` by default) is not in the group key. If `timeColumn` *is* in the group key, resulting output is confusing and generally not useful.

#### Window by calendar months and years

`every`, `period`, and `offset` parameters support all valid duration units, including calendar months (`1mo`) and years (`1y`).

#### Window by week

When windowing by week (`1w`), weeks are determined using the Unix epoch (1970-01-01T00:00:00Z UTC). The Unix epoch was on a Thursday, so all calculated weeks begin on Thursday.

##### Function type signature

```js
(
    <-tables: stream[A],
    ?createEmpty: bool,
    ?every: duration,
    ?location: {zone: string, offset: duration},
    ?offset: duration,
    ?period: duration,
    ?startColumn: string,
    ?stopColumn: string,
    ?timeColumn: string,
) => stream[B] where A: Record, B: Record
```

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

## Parameters

### every

Duration of time between windows.

### period

Duration of windows. Default is the `every` value.

`period` can be negative, indicating the start and stop boundaries are reversed.

### offset

Duration to shift the window boundaries by. Default is `0s`.

`offset` can be negative, indicating that the offset goes backwards in time.

### location

Location used to determine timezone. Default is the `location` option.

### timeColumn

Column that contains time values. Default is `_time`.

### startColumn

Column to store the window start time in. Default is `_start`.

### stopColumn

Column to store the window stop time in. Default is `_stop`.

### createEmpty

Create empty tables for empty window. Default is `false`.

### tables

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

## Examples

-   [Window data into 30 second intervals](#window-data-into-30-second-intervals)
-   [Window every 20 seconds covering 40 second periods](#window-every-20-seconds-covering-40-second-periods)
-   [Window by calendar month](#window-by-calendar-month)

### Window data into 30 second intervals

```js
data
    |> window(every: 30s)
```

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

View example input and output

#### Input data

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:30Z | 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:30Z | 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:30Z | 2021-01-01T00:00:20Z | 7 | t1 |

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

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:30Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |

### Window every 20 seconds covering 40 second periods

```js
data
    |> window(every: 20s, period: 40s)
```

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

View example input and output

#### Input data

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:20Z | 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:20Z | 2021-01-01T00:00:10Z | 10 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:20Z | 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:20Z | 2021-01-01T00:00:10Z | 4 | t2 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:40Z | 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:40Z | 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:40Z | 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:00Z | 2021-01-01T00:00:40Z | 2021-01-01T00:00:30Z | 17 | t1 |

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

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:20Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:40Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:40Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 4 | t1 |

| *_start | *_stop | _time | _value | *tag |
| --- | --- | --- | --- | --- |
| 2021-01-01T00:00:40Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:40Z | 2021-01-01T00:01:00Z | 2021-01-01T00:00:50Z | 1 | t2 |

### Window by calendar month

```js
data
    |> window(every: 1mo)
```

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

View example input and output

#### Input data

| *_start | *_stop | _time | _value |
| --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-01-01T00:00:00Z | 0 |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-01-16T00:00:00Z | 2 |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-01-31T00:00:00Z | 4 |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-02-15T00:00:00Z | 6 |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-03-02T00:00:00Z | 8 |
| 2021-01-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-03-17T00:00:00Z | 10 |

#### Output data

| *_start | *_stop | _time | _value |
| --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | 2021-02-01T00:00:00Z | 2021-01-01T00:00:00Z | 0 |
| 2021-01-01T00:00:00Z | 2021-02-01T00:00:00Z | 2021-01-16T00:00:00Z | 2 |
| 2021-01-01T00:00:00Z | 2021-02-01T00:00:00Z | 2021-01-31T00:00:00Z | 4 |

| *_start | *_stop | _time | _value |
| --- | --- | --- | --- |
| 2021-02-01T00:00:00Z | 2021-03-01T00:00:00Z | 2021-02-15T00:00:00Z | 6 |

| *_start | *_stop | _time | _value |
| --- | --- | --- | --- |
| 2021-03-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-03-02T00:00:00Z | 8 |
| 2021-03-01T00:00:00Z | 2021-04-01T00:00:00Z | 2021-03-17T00:00:00Z | 10 |

#### Related

-   [Window and aggregate data with Flux](/influxdb/v2/query-data/flux/window-aggregate/)
-   [InfluxQL – GROUP BY time()](/influxdb/v1/query_language/explore-data/#the-group-by-clause)

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