Verifying Supplier Bank Account Details at all levels

SELECT 'Bank Account At Supplier Site Level' Bank_Account_Level
     , sup.segment1
     , sup.vendor_name
     , epa.org_id
     , ss.vendor_site_code
     , NULL   Party_Site_Code
     , eba.bank_account_num
     , piu.order_of_preference priority
     , eba.ext_bank_account_id
  FROM ap_suppliers sup
     , ap_supplier_sites_all       ss
     , iby_external_payees_all epa
     , iby_pmt_instr_uses_all  piu
     , iby_ext_bank_accounts   eba
 WHERE sup.vendor_id     = ss.vendor_id
   AND ss.vendor_site_id = epa.supplier_site_id
   AND epa.ext_payee_id  = piu.ext_pmt_party_id      
   AND piu.instrument_id = eba.ext_bank_account_id
   AND sup.segment1      = :a
UNION
SELECT 'Bank Account at Supplier Level'
     , sup.segment1
     , sup.vendor_name
     , epa.org_id
     , NULL
     , NULL
     , eba.bank_account_num
     , piu.order_of_preference priority
     , eba.ext_bank_account_id
  FROM ap_suppliers sup
     , iby_external_payees_all epa
     , iby_pmt_instr_uses_all  piu
     , iby_ext_bank_accounts   eba
 WHERE sup.party_id        = epa.payee_party_id
   AND epa.ext_payee_id    = piu.ext_pmt_party_id      
   AND piu.instrument_id   = eba.ext_bank_account_id
   AND sup.segment1        = :a
   AND supplier_site_id    IS NULL
   AND party_site_id       IS NULL
UNION
SELECT 'Bank Account at Address + Opearting Unit Level'
     , sup.segment1
     , sup.vendor_name
     , epa.org_id
     , NULL
     , psite.party_site_name
     , eba.bank_account_num
     , piu.order_of_preference priority
     , eba.ext_bank_account_id
  FROM ap_suppliers            sup
     , hz_party_sites          psite
     , iby_external_payees_all epa
     , iby_pmt_instr_uses_all  piu
     , iby_ext_bank_accounts   eba
 WHERE sup.party_id        = psite.party_id
   AND psite.party_site_id = epa.party_site_id
   AND epa.ext_payee_id    = piu.ext_pmt_party_id      
   AND piu.instrument_id   = eba.ext_bank_account_id
  AND sup.segment1        = :a
   AND supplier_site_id    IS NULL
   AND epa.org_id          IS NOT NULL
UNION
SELECT 'Bank Account at Address Level'
     , sup.segment1
     , sup.vendor_name
     , epa.org_id
     , NULL
     , psite.party_site_name
     , eba.bank_account_num
     , piu.order_of_preference priority
     , eba.ext_bank_account_id
  FROM ap_suppliers            sup
     , hz_party_sites          psite
     , iby_external_payees_all epa
     , iby_pmt_instr_uses_all  piu
     , iby_ext_bank_accounts   eba
 WHERE sup.party_id        = psite.party_id
   AND psite.party_site_id = epa.party_site_id
   AND epa.ext_payee_id    = piu.ext_pmt_party_id      
   AND piu.instrument_id   = eba.ext_bank_account_id
   AND sup.segment1        = :a
   AND supplier_site_id    IS NULL
   AND epa.org_id          IS NULL
 ORDER BY bank_account_num