Flux query syntax help

Grafana InfluxDB
1

Hi,

I use graphana to querry some influxDb value.

I have temperature, Humidity, timestamp, ID and EUI

If I make a querry without EUI or ID, all work well

On my querry I would like to have only the value with ID 1

I make this querry and it return 0 row

from(bucket: "borealis")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "borealis")
  |> filter(fn: (r) => r["_field"] == "TEMPERATURE")
  |> filter(fn: (r) => r["_field"] == "ID" == 1)
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")

Same question about the EUI line. The exception is it,s a string instead of a int

from(bucket: "borealis")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "borealis")
  |> filter(fn: (r) => r["_field"] == "TEMPERATURE")
  |> filter(fn: (r) => r["_field"] == "EUI" == 2CF7F1C052400221)
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")
2

Can you show table view of your data when you query it without filter by ID?

Did you try something like this:

  |> filter(fn: (r) => r["ID"] == 1)

  |> filter(fn: (r) => r["EUI"] == "2CF7F1C052400221")
3

I have difficulty to figure how it really work.

I useNode-Red to store a value in Influx. The payload I send is something like this

image
image275×105 3.71 KB

When I check the influx database, both data seem to be in different line

image
image1682×707 59.1 KB

What I want is a querry only showing the temperature if ID of the sensor is 1

4

Ok I achieve it By changinf the field name directly by TEMPERATURE1 TEMPERATURE2

5

You should use ID and EUI as tags, not as fields if they are used to identify unique metric.

In Node-RED you can prepare your payload like this:

msg.payload = [
    {
        measurement: "borealis",
        fields: {
            TEMPERATURE: 3.94
        },
        tags: {
            ID: 1,
            EUI: "2CF7F1C0435003CF",
        },
    },
    {
        measurement: "borealis",
        fields: {
            TEMPERATURE: 5.48
        },
        tags: {
            ID: 2,
            EUI: "2CF7F1C052400221",
        },
        timestamp: new Date()
    },      
];
return msg;

And then use influx batch node from node-red-contrib-influxdb so as to save data into InfluxDB.

Then you can easily filter by ID:

ID1
ID11799×829 76.3 KB

ID2
ID21793×831 76.2 KB

Or by EUI:

EUI
EUI1799×857 76.5 KB

Corresponding Flux queries would be:

from(bucket: "DATA")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "borealis")
  |> filter(fn: (r) => r["_field"] == "TEMPERATURE")
  |> filter(fn: (r) => r["ID"] == "1")
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")

from(bucket: "DATA")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "borealis")
  |> filter(fn: (r) => r["_field"] == "TEMPERATURE")
  |> filter(fn: (r) => r["EUI"] == "2CF7F1C0435003CF")
  |> aggregateWindow(every: v.windowPeriod, fn: mean, createEmpty: false)
  |> yield(name: "mean")
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