There's probably a more elegant way, but I think this will work.
- Create a summary field in the parent table counting the number of work requests related to the parent record with blanks in work request date fields. Because additional matching criteria in summary fields ALL must be true, you might have to do this step for each date field you want to test. Like I said, not very elegant.
- Create a formula field in the master table that gives you the maximum date if the # of Blanks summary field is 0 or gives you a blank or a message if the # of Blanks summary field > 0.
If you want screenshots or formulas as examples, just let me know.
