55 lines
1.5 KiB
Markdown
55 lines
1.5 KiB
Markdown
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Use the [`cumulativeSum()` function](/flux/v0/stdlib/universe/cumulativesum/)
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to calculate a running total of values.
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`cumulativeSum` sums the values of subsequent records and returns each row updated with the summed total.
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{{< flex >}}
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{{% flex-content "half" %}}
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**Given the following input table:**
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| _time | _value |
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| ----- |:------:|
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| 0001 | 1 |
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| 0002 | 2 |
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| 0003 | 1 |
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| 0004 | 3 |
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{{% /flex-content %}}
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{{% flex-content "half" %}}
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**`cumulativeSum()` returns:**
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| _time | _value |
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| ----- |:------:|
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| 0001 | 1 |
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| 0002 | 3 |
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| 0003 | 4 |
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| 0004 | 7 |
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{{% /flex-content %}}
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{{< /flex >}}
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{{% note %}}
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The examples below use the [example data variable](/influxdb/version/query-data/flux/#example-data-variable).
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{{% /note %}}
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##### Calculate the running total of values
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```js
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data
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|> cumulativeSum()
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```
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## Use cumulativeSum() with aggregateWindow()
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[`aggregateWindow()`](/flux/v0/stdlib/universe/aggregatewindow/)
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segments data into windows of time, aggregates data in each window into a single
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point, then removes the time-based segmentation.
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It is primarily used to [downsample data](/influxdb/version/process-data/common-tasks/downsample-data/).
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`aggregateWindow()` expects an aggregate function that returns a single row for each time window.
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To use `cumulativeSum()` with `aggregateWindow`, use `sum` in `aggregateWindow()`,
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then calculate the running total of the aggregate values with `cumulativeSum()`.
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<!-- -->
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```js
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data
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|> aggregateWindow(every: 5m, fn: sum)
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|> cumulativeSum()
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```
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