I have a list of names in a REF column. I would like to limit my users to entering only one REF record per name. Therefore, I would like to apply a valid_if statement to the REF column to remove options for which a record already exists.
I am wracking my brain trying to get this to work… I have tried so many combinations of SELECT() and IN() that I’m sure I’m working in circles at this point.
Has anyone done this before that can give some insight?