LOGIC TEST: Is there a way to perform a logic test whereby in the absence of a record you can prevent an action? Example: We want to prevent the approval of a Custom Record if a joined Expense Record is Null/Zero or Absent. We can get there if the Expense record is null/zero but can't figure out the logic for "Absent". Thoughts?

I'd script a box getting check/unchecked when record is loaded based on conditions, and then use that box as my workflow constraint