---
title: duplicate() function
description: duplicate() duplicates a specified column in a table.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/duplicate/
estimated_tokens: 1350
product: Flux
version: v0
---

# duplicate() function

-   Flux 0.7.0+
-   View InfluxDB support

`duplicate()` duplicates a specified column in a table.

If the specified column is part of the group key, it will be duplicated, but the duplicate column will not be part of the output’s group key.

##### Function type signature

```js
(<-tables: stream[A], as: string, column: string) => stream[B] where A: Record, B: Record
```

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

## Parameters

### column

(Required) Column to duplicate.

### as

(Required) Name to assign to the duplicate column.

If the `as` column already exists, it will be overwritten by the duplicated column.

### tables

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

## Examples

### Duplicate a column

```js
import "sampledata"

sampledata.int()
    |> duplicate(column: "tag", as: "tag_dup")
```

[](#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 | tag_dup |
| --- | --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 | t1 |
| 2021-01-01T00:00:10Z | 10 | t1 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 | t1 |

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

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