Help with Validation Formula
I need to validate that a field YBImage has only 5 char the first char must be either A B C or D and the remaining 4 char must be numeric.
I know I can check the length with
Length ( YBImage) = 5
and I can check the total contents with
Filter ( YBImage; "0123456789ABCD"=YBImage
from there I am lost. How do I check to be sure the alfa char is in the first position?