I’m not 100% sure if I understood your questions correctly. I will try to answer in the best possible way.
Äh, yes, sure, sorry, it’s influxdb 
Here I’m not sure if I give the expected answer, but a line in my data would look something like this:
room_temp,device_id=eui-70b3d57ed006478e,host=SmartCity,topic=v3/ow-esp32-otaa@ttn/devices/eui-70b3d57ed006478e/up temperature=21.8
What I want to do is to monitor how many datapoints I have received in an hour. Since I know that the sensor is supposed to send a new value each 5 min, I should have 12 entries in the database per hour.
For that I’m using this InfluxQL query:
SELECT count("temperature") FROM "room_temp" WHERE ("device_id"::tag = 'eui-70b3d57ed006478e') GROUP BY time(60m)
It works (more or less, but that is another question, raised here: GROUP BY time - want to look backwards / handling timing deviations).
When I have received less than, let’s say 11 datapoints in an hour I would highlight that on the dashboard (= critical value).