I'd like to recommend checking the Forums as a good first step-- you just might discover your question has already been asked (and answered!).
I was able to find this, plus several others:
If that doesn't do the trick-- just hold on a second! I know from experience that there are MANY Tableau Zen Masters here that will jump on your example to lend a hand!
If it's always yesterday that will be reported on this becomes slightly easier. This formula can be modified, replacing the hardcoded date with a formula to reference yesterday (such as DATEADD('day',-1,TODAY())):
COUNT(IF [Submit Date] = #01/01/2016# THEN [Ticket Number] END) -
COUNT(IF [Processed Date] = #01/01/2016# and [Was Returned] = 'yes' then [Ticket Number] END)