Multiple Format Validation Calculation
I am new to Filemaker and trying to write a calculation for field validation that covers two possible formats for the same field. I have tried various forms of case and if statements that all seem like they should work, but I'm apparently doing something wrong. Can anyone here help me figure this out?
I need a field to be either 4 characters or 7 characters. If it is 4 characters, I need it to be filtered to just numerals. If it is 7 characters, I need the first three characters to be INV and the last 4 characters to be numerals. So the two possible formats are "####" and "INV####." Am I trying to do too much with a single field here?