---
title: experimental.count() function
description: >
  `experimental.count()` returns the number of records in each input table.
menu:
  flux_v0_ref:
    name: experimental.count
    parent: experimental
    identifier: experimental/count
weight: 101
flux/v0/tags: [transformations, aggregates]
introduced: 0.107.0
---

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`experimental.count()` returns the number of records in each input table.

The count is returned in the `_value` column and counts both null and non-null records.

#### Counts on empty tables
`experimental.count()` returns 0 for empty tables.
To keep empty tables in your data, set the following parameters when using
the following functions:

```
filter(onEmpty: "keep")
window(createEmpty: true)
aggregateWindow(createEmpty: true)
```

##### Function type signature

```js
(<-tables: stream[{A with _value: B}]) => stream[{A with _value: int}]
```

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

## Parameters

### tables

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




## Examples

### Count the number of rows in a table

```js
import "experimental"
import "sampledata"

sampledata.int()
    |> experimental.count()

```

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{{% 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 | _value  |
| ---- | ------- |
| t1   | 6       |

| *tag | _value  |
| ---- | ------- |
| t2   | 6       |

{{% /expand %}}
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