I want to build an average hourly revenue report for some period, for example, for a month. If I count it manually for 00:00-00:59 I sum all revenues from 00:00 till 00:59 and divide by number of days I want to get average for.

In Zoho Reports I've made an aggregate formula for Sum of Revenue:

sum("Sales Raw Data"."Revenue")/count(Distinct(date("Sales Raw Data"."Purchase date")))

and then tried to build a chart with hours on X axis. The problem is that the aggregate formula doesn't include missing hours and the running total of average is calculated wrong. For example, I have few or none sales during night hours, so there are no data for them, but they still have to be counted to get correct average.