A blank description can throw an error on the front end when looking at invoices. The script below will find all invoices with blank descriptions.
select a.Customer_Number,
b.Invoice_Number, b.Invoice_Id, c.description
from AR_Customer a, ar_invoice b, AR_Invoice_Item c
where a.customer_id = b.Customer_Id
and c.Invoice_Id = b.Invoice_Id
and c.Description = ''
order by a.Customer_Number, b.Invoice_Number