Count Unique Values in a Date Range

Thank you for your response here.  This isn't quite what I was looking for.  If I'm reading that correct, is that the number of studies that have a start AND an end date occurring between 01-JAN-2023 and 28-FEB-2023?

My current task is to figure out the number of studies with a Phase of "Pre-Treatment" and a start date within the selected date range. So,  if the user selects the month of January in the date filter, then by looking at your table above, the count would be 2 because there are 2 studies with a Stage of "Pre-Treatment" and a start date in January.  It doesnt' matter when that phase ends because all we are interested in is if the "Receipt / Transfer" phase starts in the selected date range. 

Hopefully that all makes sense!

Thanks again.