Azure Application Insights Query - How to calculate percentage of total - azure

Question

I'm trying to create a row in an output table that would calculate percentage of total items:
Something like this:
ITEM | COUNT | PERCENTAGE
item 1 | 4 | 80
item 2 | 1 | 20
I can easily get a table with rows of ITEM and COUNT, but I can't figure out how to get total (5 in this case) as a number so I can calculate percentage in column %.
someTable
| where name == "Some Name"
| summarize COUNT = count() by ITEM = tostring( customDimensions.["SomePar"])
| project ITEM, COUNT, PERCENTAGE = (C/?)*100
Any ideas? Thank you.

Answer 1

It's a bit messy to create a query like that.
I've done it bases on the customEvents table in AI. So take a look and see if you can adapt it to your specific situation.
You have to create a table that contains the total count of records, you then have to join this table. Since you can join only on a common column you need a column that has always the same value. I choose appName for that.
So the whole query looks like:
let totalEvents = customEvents
// | where name contains "Opened form"
| summarize count() by appName
| project appName, count_ ;
customEvents
// | where name contains "Opened form"
| join kind=leftouter totalEvents on appName
| summarize count() by name, count_
| project name, totalCount = count_ , itemCount = count_1, percentage = (todouble(count_1) * 100 / todouble(count_))
If you need a filter you have to apply it to both tables.
This outputs:

Answer 2

It is not even necessary to do a join or create a table containing your totals
Just calculate your total and save it in a let like so.
let totalEvents = toscalar(customEvents
| where timestamp > "someDate"
and name == "someEvent"
| summarize count());
then you can simply add a row to your next table, where you need the percentage calcualtion by doing:
| extend total = totalEvents
This will add a new column to your table filled with the total you calculated.
After that you can calculate the percentages as described in the other two answers.
| extend percentages = todouble(count_)*100/todouble(total)
where count_ is the column created by your summarize count() which you presumably do before adding the percentages.
Hope this also helps someone.

Answer 3

I think following is more intuitive. Just extend the set with a dummy property and do a join on that...
requests
| summarize count()
| extend a="b"
| join (
requests
| summarize count() by name
| extend a="b"
) on a
| project name, percentage = (todouble(count_1) * 100 / todouble(count_))

Answer 4

This might work too:
someTable
| summarize count() by item
| as T
| extend percent = 100.0*count_/toscalar(T | summarize sum(count_))
| sort by percent desc
| extend row_cumsum(percent)