Vendors with no Invoices

select segment1 VENDOR NBR,
vendor_name NAME,
vendor_site_code SITE_CODE,
end_date_active VEND_INACTIVE,
inactive_date SITE_INACTIVE
from po_vendors vend,
po_vendor_sites_all sites,
ap_invoices_all inv
where vend.vendor_id = sites.vendor_id
and sites.vendor_site_id = inv.vendor_site_id(+)
and inv.vendor_site_id is null;