Calculation based on date of each dataset

Fluxlang
1

HI All,

I’d like to do some calculations based on the date of the respective dataset.

I have a dataset which let’s say:

2024-01-02T00:00:00.000Z / 5017.609999999404
2024-01-03T00:00:00.000Z / 21893.759999999776
2024-01-04T00:00:00.000Z / 19366.27999999933

Now I need to do some calculation based on the date, meaning that on Jan 2nd e.g. plus 2, Jan 3rd plus 5, and so on. I have a formula/table which calculates what to add based on the date.

Background: The daily values are the cumulated production of my PV panels. I have as well the predication based on the simulation software as daily average per month. Now I would like to have for each day the cumulated difference between the actual production and the prediction for the current year until the current day.

Thanks!
Oliver

2

You will need to use map() to perform this calculation for the given date, something like this:

from(bucket: "your_bucket")
  |> range(start: 2024-01-01T00:00:00Z, stop: 2024-01-05T00:00:00Z)
  |> filter(fn: (r) => r._measurement == "your_measurement")
  |> map(fn: (r) => ({
      r with 
      _value: if r._time == 2024-01-02T00:00:00Z then r._value + 2
             else if r._time == 2024-01-03T00:00:00Z then r._value + 5
             else if r._time == 2024-01-04T00:00:00Z then r._value + 3
             else r._value
    }))
3

Ah, thanks, r._time was what I was looking for. With that I can do my calculation as you suggested.

1 Like