InfluxDB Flux - get count of distinct occurrences

Fluxlang
1

I’m trying to get a count of unique occurrences of a tag. I’m using a ‘filter’ to select the relevant data, then distinct to return only the distinct values. The problem is, distinct seems to return 2 tables. My Flux query is:

from(bucket:"areaEvent")
  |> range(start: 2020-07-21T09:00:00.00Z, stop: 2020-07-21T09:10:00Z)
  |> filter(fn: (r) =>
    r._measurement == "areaEvent" and
    r.areaId == "area_2"
  )
  |> keep(columns: ["visitorId"])
  |> distinct(column: "visitorId")
  |> count()

The output is:

Result: _result
Table: keys: [visitorId]
      visitorId:string                  _value:int  
----------------------  --------------------------  
                abc125                           1  
Table: keys: [visitorId]
      visitorId:string                  _value:int  
----------------------  --------------------------  
                abc126                           1

How would I just get an output value of ‘2’, which is the count of distinct visitor IDs that appear in this result?

2

I’m still learning this myself, but it seems that flux has a notion of lists of tables in the output of a query. And that operations are applied to each table individually .

Try using group()

More info here

3

Thank you very much! That is very helpful and provides the solution.

Regards,

Rob

4

No worries, can you mark the comment with the solution so it helps others that run into this issue in future :+1:

5

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