I have a custom field which contains an external ID. I want to create a validation rule that permits Blank values after evaluating the field for data. If there is data in the field, I want the validation rule to enforce numbers only (format of the external ID). I believe this would be achieved with a nested IF statement but have not been able to find the correct syntax to make this work. Thanks in advance!
2 answers
You could use a Formula like this
AND(
NOT(ISBLANK( FieldName )),
NOT(ISNUMBER( FieldName ))
)
