Json input - calculated with derived values like unique-count


(Dor Juravski) #1

Hi, I know how to use json input to display a simple calculation on 2 fields.
For example

{ "script": 
"_value / doc['number_field1'] .value "
}

What I don't know is how to do a calculation on an aggregated field. For example unique count.
For example

{ "script": 
"_value / unique_count(doc['number_field1'] .value) "
}

In my visialization I created a line graph showing the unique count over time.
So is there a way to access that field in the visualization?

Thank you!


(Lee Drengenberg) #2

You can just create a Metric visualization if you just want to display that unique count;


(Dor Juravski) #3

I wish, it's a line graph showing unique_count(field A) and unique_count(field B) over time.
I just need to show a calculation of those 2
unique_count(field A) / unique_count(field B) over time

I'm 100% sure there is a way, because it's fields in the JSON that creates the graph elements.
Not familiar enough with Kibana to find out how.


(Lee Drengenberg) #4

OK, for the simple case, you can just use the unique count metric like this;

If you need to divide 2 unique counts over time, I think the Visual Builder could do that.

In the Visual Builder unique count is Cardinality.

It starts looking very similar like this;

I can add a second metric, and then a third that I switch to a Calculation. Then create a variable for each of the 2 metrics. Then use them in a simple division.

Does this get you what you're looking for?


(Dor Juravski) #5

2 cardinality fields created, and then the "calculation" option is grayed out.
Maybe because I am using cardinality with string/keyword fields?


(Lee Drengenberg) #6

There was an issue about that. What version are you on?


(Dor Juravski) #7

6.2.1


(Dor Juravski) #8

I tried one more thing - took 2 metrics who's average is known to me and calculation was allowed this time (great!) but the result just gave me nothing. See screenshot
In the data - the first average is 21 and the second is 15, so I was hoping to see 1.4


(Lee Drengenberg) #9

Can you show a screenshot of the "Time Series" tab? By default, the Metric tab you're on will show the last value in your Time Series. So if that Time Series drops off to 0 at the end, that's what you would see in the Metric tab. But there is a way to get the overall average as well.


(Dor Juravski) #10

Screenshot attached - when putting either field on top there is no zero value.
Interesting. How do I get the overall average?


(Lee Drengenberg) #11

This is kind of a long discuss thread but there are some notes about using Overall Average in it;


(system) #12

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