aggregateWindow() function
aggregateWindow()
groups data into fixed windows of time and applies an
aggregate or selector function to each window.
All columns not in the group key other than the specified column
are dropped
from output tables. This includes _time
. aggregateWindow()
uses the
timeSrc
and timeDst
parameters to assign a time to the aggregate value.
aggregateWindow()
requires _start
and _stop
columns in input data.
Use range()
to assign _start
and _stop
values.
Window by calendar months and years
every
, period
, and offset
parameters support all valid duration units,
including calendar months (1mo
) and years (1y
).
Window by week
When windowing by week (1w
), weeks are determined using the Unix epoch
(1970-01-01T00:00:00Z UTC). The Unix epoch was on a Thursday, so all
calculated weeks begin on Thursday.
Function type signature
(
<-tables: stream[D],
every: duration,
fn: (<-: stream[B], column: A) => stream[C],
?column: A,
?createEmpty: bool,
?location: {zone: string, offset: duration},
?offset: duration,
?period: duration,
?timeDst: string,
?timeSrc: string,
) => stream[E] where B: Record, C: Record, D: Record, E: Record
Parameters
every
(Required) Duration of time between windows.
period
Duration of windows. Default is the every
value.
period
can be negative, indicating the start and stop boundaries are reversed.
offset
Duration to shift the window boundaries by. Defualt is 0s
.
offset
can be negative, indicating that the offset goes backwards in time.
fn
(Required) Aggreate or selector function to apply to each time window.
location
Location used to determine timezone. Default is the location
option.
column
Column to operate on.
timeSrc
Column to use as the source of the new time value for aggregate values.
Default is _stop
.
timeDst
Column to store time values for aggregate values in.
Default is _time
.
createEmpty
Create empty tables for empty window. Default is false
.
Note: When using createEmpty: true
, aggregate functions return empty
tables, but selector functions do not. By design, selectors drop empty tables.
tables
Input data. Default is piped-forward data (<-
).
Examples
- Use an aggregate function with default parameters
- Specify parameters of the aggregate function
- Window and aggregate by calendar month
Use an aggregate function with default parameters
data
|> aggregateWindow(every: 20s, fn: mean)
Specify parameters of the aggregate function
To use functions that don’t provide defaults for required parameters with
aggregateWindow()
, define an anonymous function with column
and tables
parameters that pipes-forward tables into the aggregate or selector function
with all required parameters defined:
data
|> aggregateWindow(
column: "_value",
every: 20s,
fn: (column, tables=<-) => tables |> quantile(q: 0.99, column: column),
)
Window and aggregate by calendar month
data
|> aggregateWindow(every: 1mo, fn: mean)
Was this page helpful?
Thank you for your feedback!
Support and feedback
Thank you for being part of our community! We welcome and encourage your feedback and bug reports for Flux and this documentation. To find support, use the following resources:
InfluxDB Cloud customers can contact InfluxData Support.