Stuck with a simple query to sum three values

InfluxDB 1 InfluxQL
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1

Hi,
I want to power measure my electric stove and so I have installed three shellies sending the measurement for every phase. I can select them using:

SELECT last(“ENERGY_Power”) FROM “mqtt_consumer” WHERE “topic” = ‘oben/kueche/herd/phase1/SENSOR’
SELECT last(“ENERGY_Power”) FROM “mqtt_consumer” WHERE “topic” = ‘oben/kueche/herd/phase2/SENSOR’
SELECT last(“ENERGY_Power”) FROM “mqtt_consumer” WHERE “topic” = ‘oben/kueche/herd/phase3/SENSOR’

What I want to see in grafana is a cummulated entry showing the “ENERGY_Power” summary of all three phases.
I have tried:

SELECT sum(“last”) from (SELECT last(“ENERGY_Power”) FROM “mqtt_consumer” WHERE “topic” = ‘oben/kueche/herd/phase1/SENSOR’ OR “topic” = ‘oben/kueche/herd/phase2/SENSOR’ OR “topic” = ‘oben/kueche/herd/phase3/SENSOR’) GROUP BY time(1m) fill(null)
in grafana itself but that does not show history data of the sum.

So I have some questions:

  • What am I doing wrong in this query?
  • Is it the right way, to build the sum in grafana or would it be a better way to do the calculation in influxdb and put the cummulated value into an own field on every insert of phase1/2/3? And If so - I unfurtunately have no idea how to.

Thank you!

Kind regards,
Jan

2

Hello @FerFemNemBem,
I’m not sure but ca you try:

SELECT sum(“last”) from (SELECT last(“ENERGY_Power”) FROM “mqtt_consumer” WHERE “topic” = ‘oben/kueche/herd/phase1/SENSOR’ OR “topic” = ‘oben/kueche/herd/phase2/SENSOR’ OR “topic” = ‘oben/kueche/herd/phase3/SENSOR’ AS "last") GROUP BY time(1m) fill(null)

thanks