Azure Log Analytics - KQL - query for getting year-to-date count

Question

I want to write a query in Azure Log Analytics to get month-to-date and year-to-date data for number of VMs. I already have a month-to-date table below. I want to use below to get year-to-date count against each month by simply adding count for all previous months.

e.g current month-to-date dataset

what I want the result to be is:

Answer 1

The row_cumsum() function will do exactly what you're looking for.