Login history with empty value for some users

Hi there
I want to generate a login history dataset.
I would like to have some userid with no login date. By using “% blank” the number of not connected is a bit too low. So I apply it also on the userid field to have the expected results but I need to join another table later in the process. Anyway.
For those with login date, I would like to have kind of ramp up or at least with some drop off on weekend for example.
Is there a way to do it ?
Thanks