---
title: duplicate() function
description: duplicate() duplicates a specified column in a table.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/duplicate/
estimated_tokens: 895
product: Flux
version: v0
publisher: InfluxData
canonical: https://docs.influxdata.com/flux/v0/stdlib/universe/duplicate/
date: '2024-04-08T16:01:02-06:00'
lastmod: '2024-04-08T16:01:02-06:00'
---

* Flux 0.7.0+

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/)
| _time | _value | *tag |
| --- | --- | --- |
| _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 |
| --- | --- | --- |
| _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 |

| _time | _value | *tag | tag_dup |
| --- | --- | --- | --- |
| _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 |
| --- | --- | --- | --- |
| _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 |