supplier unpaid query( Iink between po_headers_all and ap_invoices_all)

  SELECT   DISTINCT ou.name "OPERATING UNIT",
                    pv.segment1 "Supplier GSL",
                    pv.vendor_name "Supplier Name"  ,
                    apt1.name "Supplier Header Terms",
                    apt.NAME "Supplier Site Terms",
                    ph.segment1 "PO#",
                    ph.CLOSED_CODE "PO Status",
                    (SELECT   name
                       FROM   ap_terms
                      WHERE   term_id = ph.terms_id)
                       "PO Terms",
                    aia.invoice_num,
                    (SELECT   name
                       FROM   ap_terms
                      WHERE   term_id = aia.terms_id)
                       "AP Terms",
                  decode(CANCELLED_DATE,null,'', 'Cancelled')   "AP Status"
    --      ,apt.description
    --      ,pvsa.PAY_DATE_BASIS_LOOKUP_CODE "Pay Date Basis"
    FROM   apps.AP_SUPPLIERS pv,
           apps.AP_SUPPLIER_SITES_ALL pvsa,
           apps.ap_invoices_all aia,
          -- apps.ap_invoice_payments_all aip,
           ap_invoice_distributions_all aida,
           (SELECT   *
              FROM   apps.ap_terms_tl
             WHERE   lANGUAGE = 'US') apt,
           (SELECT   *
              FROM   apps.ap_terms_tl
             WHERE   lANGUAGE = 'US') apt1,
           po_headers_all ph,
           po_lines_all pla,
           po_distributions_all pda,
           hr_operating_units ou,
           ap_tolerance_templates att
   WHERE       pv.vendor_id = pvsa.vendor_id
           AND pv.vendor_id = aia.vendor_id
           AND pvsa.VENDOR_SITE_ID = aia.VENDOR_SITE_ID
           AND ou.organization_id = pvsa.org_id
          -- AND aip.invoice_id = aia.invoice_id
           AND pvsa.TERMS_ID = apt.TERM_ID(+)
           AND pv.TERMS_ID = apt1.TERM_ID(+)
           AND pvsa.TOLERANCE_ID = att.TOLERANCE_ID(+)
           AND ph.vendor_id = pv.vendor_id
           AND ph.org_id = pvsa.org_id
           AND ph.po_header_id = pla.po_header_id
           AND ph.org_id = pla.org_id
           AND ph.po_header_id = pda.po_header_id
           AND pla.po_line_id = pda.po_line_id
           AND ph.org_id = pda.org_id
           AND aida.invoice_id = aia.invoice_id
           AND pda.org_id = aida.org_id
           AND aia.org_id = aida.org_id
           AND pda.po_distribution_id = aida.po_distribution_id
           AND aia.PAYMENT_STATUS_FLAG = 'N'
           AND NVL (pv.end_DATE_ACTIVE, SYSDATE) >= SYSDATE
         -- and ph.segment1 ='700021845'
          --and CANCELLED_DATE is null
         --  AND pv.segment1 = 'E52029'
ORDER BY   pv.segment1 ASC