---
title: join.time() function
description: join.time() joins two table streams together exclusively on the _time column.
url: https://docs.influxdata.com/flux/v0/stdlib/join/time/
estimated_tokens: 760
product: Flux
version: v0
publisher: InfluxData
canonical: https://docs.influxdata.com/flux/v0/stdlib/join/time/
date: '2024-04-08T16:01:02-06:00'
lastmod: '2024-04-08T16:01:02-06:00'
---

* Flux 0.172.0+

InfluxDB support

`join.time()` joins two table streams together exclusively on the `_time` column.

This function calls `join.tables()` with the `on` parameter set to `(l, r) => l._time == r._time`.

##### Function type signature

```js
(
    <-left: stream[{A with _time: B}],
    as: (l: {A with _time: B}, r: {C with _time: D}) => E,
    right: stream[{C with _time: D}],
    ?method: string,
) => stream[E] where B: Equatable, D: Equatable, E: Record
```

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

## Parameters

### left

Left input stream. Default is piped-forward data (\<-).

### right

(Required)
Right input stream.

### as

(Required)
Function that takes a left and a right record (`l` and `r` respectively), and returns a record.
The returned record is included in the final output.

### method

String that specifies the join method. Default is `inner`.

**Supported methods:**

* inner
* left
* right
* full

## Examples

### Join two tables by timestamp

```js
import "sampledata"
import "join"

ints = sampledata.int()
strings = sampledata.string()

join.time(left: ints, right: strings, as: (l, r) => ({l with label: r._value}))
```

[](#view-example-output)

View example output

#### Output data

|       \_time       |\_value|   label    |\*tag|
|--------------------|-------|------------|-----|
|2021-01-01T00:00:00Z|  \-2  |smpl\_g9qczs| t1  |
|2021-01-01T00:00:10Z|  10   |smpl\_0mgv9n| t1  |
|2021-01-01T00:00:20Z|   7   |smpl\_phw664| t1  |
|2021-01-01T00:00:30Z|  17   |smpl\_guvzy4| t1  |
|2021-01-01T00:00:40Z|  15   |smpl\_5v3cce| t1  |
|2021-01-01T00:00:50Z|   4   |smpl\_s9fmgy| t1  |

|       \_time       |\_value|   label    |\*tag|
|--------------------|-------|------------|-----|
|2021-01-01T00:00:00Z|  19   |smpl\_b5eida| t2  |
|2021-01-01T00:00:10Z|   4   |smpl\_eu4oxp| t2  |
|2021-01-01T00:00:20Z|  \-3  |smpl\_5g7tz4| t2  |
|2021-01-01T00:00:30Z|  19   |smpl\_sox1ut| t2  |
|2021-01-01T00:00:40Z|  13   |smpl\_wfm757| t2  |
|2021-01-01T00:00:50Z|   1   |smpl\_dtn2bv| t2  |

#### Related

* [Join on time](/flux/v0/join-data/time/)
* [Troubleshoot join operations](/flux/v0/join-data/troubleshoot-joins/)

[transformations](/flux/v0/tags/transformations/)
| _time | _value | label | *tag |
| --- | --- | --- | --- |
| _time | _value | label | *tag |
| 2021-01-01T00:00:00Z | -2 | smpl_g9qczs | t1 |
| 2021-01-01T00:00:10Z | 10 | smpl_0mgv9n | t1 |
| 2021-01-01T00:00:20Z | 7 | smpl_phw664 | t1 |
| 2021-01-01T00:00:30Z | 17 | smpl_guvzy4 | t1 |
| 2021-01-01T00:00:40Z | 15 | smpl_5v3cce | t1 |
| 2021-01-01T00:00:50Z | 4 | smpl_s9fmgy | t1 |

| _time | _value | label | *tag |
| --- | --- | --- | --- |
| _time | _value | label | *tag |
| 2021-01-01T00:00:00Z | 19 | smpl_b5eida | t2 |
| 2021-01-01T00:00:10Z | 4 | smpl_eu4oxp | t2 |
| 2021-01-01T00:00:20Z | -3 | smpl_5g7tz4 | t2 |
| 2021-01-01T00:00:30Z | 19 | smpl_sox1ut | t2 |
| 2021-01-01T00:00:40Z | 13 | smpl_wfm757 | t2 |
| 2021-01-01T00:00:50Z | 1 | smpl_dtn2bv | t2 |