Our sales manager wants a report for Zoho CRM that shows all contacts that have not had notes written for them in the past 30 days. I can bring up all contacts that have had no notes ever by using Contact and Note as the joined tables, and using 'Note Content is Empty' as an advanced filter -- this seems to only show items that have no notes at all. 

However, I can't properly generate a report that would show items with no notes in the period; using 'Note Creation Date > 30 days' will merely give me every note placed that is older, and will not give me 'every contact that has no notes less than 30 days old.' Any thoughts?