I am very new to this so apologise if its something simple I’ve missed but I have been looking at this all day.
I have a basic temp and humidity sensor on my RPi2 logging data to a a InfluxDB table. Its working fine.
I am trying to plot a graph that shows the temp history. When I use the most basic of settings nothing appears, if I go into the query editor I can see the query as:
SELECT mean(“temperature”) FROM “rpi-dht22” WHERE $timeFilter GROUP BY time(5m) fill(null)
If I remove the Group By it displays a single data point.
It currently writes to the table every 60 seconds, so in my Influx settings are 5m and I have also tried 1m.
Hello. Did you try:
SELECT distinct(“temperature”) FROM “rpi-dht22” WHERE $timeFilter GROUP BY time(1m) fill(null)
?
Did you try to put this query in the influxdb command line interface?
@thisispete have you verified you’re using a valid time range (upper right corner) and that you’re using UTC timezone for storing your series in influxdb?
I have a similar problem with a similar project (temp sensor on RPi Zero with InfluxDB + Grafana):
I can query a single data point by removing the Group By option and using this query in Grafana or in the InfluxDB CLI:
SELECT last(“temperature”) FROM “Fahrenheit” WHERE time >= now() - 5m
However, if I add GROUP BY to the query to try and create a chart, I get no data in either Grafana or the InfluxDB CLI:
SELECT mean(“temperature”) FROM “Fahrenheit” WHERE time >= now() - 5m GROUP BY time(1m) fill(null)
Note: I have set my minimum time interval to various settings 1s, 1m, etc… (FYI: The temp data is checked every 1s.)
Any suggestions?
You need to select the time as well as the temperature, otherwise there is no timestamp against each sample.
select time, mean("temperature") from ....
