How to validate if an attachment record has been created but the attachment file is missing

Summary:

When submitting a requisition, is it possible to perform user validation using custom SQL and display an error if a problem occurs?

Content (please ensure you mask any confidential information):

In our production environment, we are experiencing an issue where attachment records are sometimes created without any actual files attached.

And this issue is causing purchase orders created from those requisitions to fail to send email PO.

Therefore, we want to perform SQL validation when a purchase requisition is submitted, and if applicable, prompt the user to update the attached record.

Version (include the version you are using, if applicable):