docs-v2/content/flux/v0/stdlib/join/time.md

title	description	menu	weight	flux/v0/tags	introduced
join.time() function	`join.time()` joins two table streams together exclusively on the `_time` column.	flux_v0_ref name parent identifier join.time join join/time	101	transformations	0.172.0

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

(
    <-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

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Parameters

left

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

right

({{< req >}}) Right input stream.

as

({{< req >}}) 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

import "sampledata"
import "join"

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

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

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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

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