Display individual and aggregated values at the same time in a scatter plot

I'm working in a scatter plot and trying to set up vertical axis.

I need to display both individual values (aggregate: (none)) and also aggregated (avg, sum ...). 

When I set up only one of them, it works as expected, however if I set both of them at the same time, I get "The expression is not valid" error. (The same happens when I try to do something similar within a custom expression)

Is there any workaround for it?

(1) Answer