I can't for the life of it figure out how to get the length or duration of a series within a given time frame in InfluxDB 1.8.
I need this to calculate kWh from a kW reading, but I would have thought lots of people would need this to e.g. calculate server uptime.
If nothing else works, I could work with getting the time between first and last point of a series, but really would like to be able to exclude any gaps in between.
I feel elapsed() may be used for that, but as the documentation says it seems to only give nonsensical results if combined with a GROUP BY time clause.
Any help would be greatly appreciated.