Let's say I have 2 fields: A and B

If A has data, then B must have a data, otherwise B can be blanked.

I can run a script to check such as: if not isempty(A) and isempty(:,

then show message,

But I like to check it by go to field definition, and click validation tab. I attempted to do this way couple times, but I always get a FMP error message

What I did is:

Case( not isempty(A) and not isempty(:, 1, 0)

and the error message look like:

An operator (eg +, -, *,..) is expected here.

What did I miss?

Thank you in advance.

HP

Where was the cursor after the error message appeared?

Try this:

Case(