Query To Get PO Number, Invoice Number and Receipt Number With one of the Input

Query To Get PO Number, Invoice Number and Receipt Number With one of the Input

SELECT distinct pha.segment1 po_number
       ,aia.invoice_num invoice_number
       ,rsh.receipt_num receipt_number
  FROM po_headers_all pha
       ,po_distributions_all pda
       ,ap_invoice_distributions_all aid
       ,ap_invoices_all aia
       ,rcv_shipment_lines rsl
       ,rcv_shipment_headers rsh
 WHERE pha.po_header_id=pda.po_header_id
   AND aid.po_distribution_id=pda.po_distribution_id
   AND aia.invoice_id=aid.invoice_id
   AND rsl.po_header_id=pha.po_header_id
   AND rsl.shipment_header_id=rsh.shipment_header_id
   AND pha.segment1=nvl(:P_PO_NUM,pha.segment1)
   AND aia.invoice_num=nvl(:P_INVOICE_NUM,aia.invoice_num)
   AND rsh.receipt_num=nvl(:P_RECEIPT_NUM,rsh.receipt_num)
 order by 2
;