Query to get UNPAID Invoices (Oracle Payables)

Below is Simple Query to get UNPAID Invoices (Oracle Payables). It also includes the condition to exclude ZERO Dollar Invoices.

select i.invoice_num,

          v.vendor_name,

          i.invoice_date,

          ps.due_date,
          i.invoice_amount,

          i.amount_paid,

          ps.amount_remaining,

          SUM(i.invoice_amount),

          sum(ps.amount_remaining)
FROM ap_payment_schedules_all ps,
            ap_invoices_all i,
            po_vendors v,
            po_vendor_sites_all vs
WHERE   i.invoice_id = ps.invoice_id
AND     i.vendor_id = v.vendor_id
AND     i.vendor_site_id = vs.vendor_site_id
AND     i.payment_status_flag ='N'
AND     (nvl(ps.amount_remaining, 0) * nvl(i.exchange_rate,1))  != 0
AND    i.cancelled_date is not null
group by v.vendor_name,

               i.invoice_num,

               i.invoice_date,

               ps.due_date,

               i.invoice_amount,  

               i.amount_paid,
               ps.amount_remaining
Order by v.vendor_name,i.invoice_num