---
title: tickscript.select() function
description: >
  `tickscript.select()` changes a column’s name and optionally applies an aggregate or selector
  function to values in the column.
menu:
  flux_v0_ref:
    name: tickscript.select
    parent: contrib/bonitoo-io/tickscript
    identifier: contrib/bonitoo-io/tickscript/select
weight: 301
flux/v0/tags: [transformations]
---

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`tickscript.select()` changes a column’s name and optionally applies an aggregate or selector
function to values in the column.

## TICKscript helper function

`tickscript.select()` is a helper function meant to replicate TICKscript operations like the following:

```
// Rename
query("SELECT x AS y")

// Aggregate and rename
query("SELECT f(x) AS y")
```

##### Function type signature

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

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

## Parameters

### column

Column to operate on. Default is `_value`.



### fn

Aggregate or selector function to apply.



### as
({{< req >}})
New column name.



### tables

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




## Examples

- [Change the name of the value column](#change-the-name-of-the-value-column)
- [Change the name of the value column and apply an aggregate function](#change-the-name-of-the-value-column-and-apply-an-aggregate-function)
- [Change the name of the value column and apply a selector function](#change-the-name-of-the-value-column-and-apply-a-selector-function)

### Change the name of the value column

```js
import "contrib/bonitoo-io/tickscript"
import "sampledata"

sampledata.int()
    |> tickscript.select(as: "example-name")

```

{{< expand-wrapper >}}
{{% expand "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                | example-name  | *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                | example-name  | *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   |

{{% /expand %}}
{{< /expand-wrapper >}}

### Change the name of the value column and apply an aggregate function

```js
import "contrib/bonitoo-io/tickscript"
import "sampledata"

sampledata.int()
    |> tickscript.select(as: "sum", fn: sum)

```

{{< expand-wrapper >}}
{{% expand "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

| *tag | sum  |
| ---- | ---- |
| t1   | 51   |

| *tag | sum  |
| ---- | ---- |
| t2   | 53   |

{{% /expand %}}
{{< /expand-wrapper >}}

### Change the name of the value column and apply a selector function

```js
import "contrib/bonitoo-io/tickscript"
import "sampledata"

sampledata.int()
    |> tickscript.select(as: "max", fn: max)

```

{{< expand-wrapper >}}
{{% expand "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                | max  | *tag |
| -------------------- | ---- | ---- |
| 2021-01-01T00:00:30Z | 17   | t1   |

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

{{% /expand %}}
{{< /expand-wrapper >}}