If the record number is a report field you can conditionally suppress (hide) the field. Right click on the field, go to Format Field, then the Common tab, Check Suppress then click on the Formula(X-2) button to the right. When the window opens enter
Count({datafield}) = 0;
This should suppress (hide) the field whenever there are not any records. Otherwise it will show. You of course will need to change the {datafield} to an appropriate field name.
Hope this helps.
Regards,
John W.