Divide by a variable/Null values

[JonathanKelly]

Hi,

I have a bar chart where I am trying to divide the bar to show an average of jobs done, however the number of people working each day varies. In the bar chart below on 26/03 only 1 person worked so this should be 25, I currently have it as dividing by 6 as that is the average of people but, how can I count how many people worked and void out Null values against for people who didn't? 

[hic · Accepted solution]

To get the average number of jobs per person, the following should work:

Count(distinct JobID) / Count(distinct PersonID)

NULLs should be automatically handled.