Query to extract Purchase Order Details

SELECT POH.SEGMENT1 "Po Number"
     , POH.TYPE_LOOKUP_CODE "Po  Type"
     , POH.AUTHORIZATION_STATUS "Po  Status"
     , POV.VENDOR_NAME "Supplier Name"
     , POVS.VENDOR_SITE_CODE "Location"
     , HRLS.LOCATION_CODE "Ship To"
     , HRLB.LOCATION_CODE "Bill To"
     , POL.LINE_NUM "Line Number"
     , MSIB.SEGMENT1 "Item"
     , POL.UNIT_PRICEm "Unit Price"
     , POL.QUANTITY "Quantity"
     , POD.AMOUNT_BILLED "Amount"
     , POD.DESTINATION_SUBINVENTORY
     , PPF.FULL_NAME "Buyer Name"
     , POH.CLOSED_CODE
FROM   PO_HEADERS_ALL POH
     , PO_LINES_ALL POL
     , MTL_SYSTEM_ITEMS_B MSIB
     , PO_LINE_LOCATIONS_ALL POLL
     , PO_DISTRIBUTIONS_ALL POD
     , PO_VENDORS POV
     , PO_VENDOR_SITES_ALL POVS
     , HR_LOCATIONS_ALL HRLS
     , HR_LOCATIONS_ALL HRLB
     , PER_ALL_PEOPLE_F PPF
     , PO_LINE_TYPES POLT
WHERE  POLT.LINE_TYPE_ID = POL.LINE_TYPE_ID
AND    POVS.VENDOR_SITE_ID = POH.VENDOR_SITE_ID
AND    POV.VENDOR_ID = POH.VENDOR_ID
AND    POL.ITEM_ID = MSIB.INVENTORY_ITEM_ID
AND    MSIB.ORGANIZATION_ID = 204
AND    POH.PO_HEADER_ID = POL.PO_HEADER_ID
AND    POL.PO_LINE_ID = POD.PO_LINE_ID
AND    POLL.LINE_LOCATION_ID = POD.LINE_LOCATION_ID
AND    POH.SHIP_TO_LOCATION_ID = HRLS.LOCATION_ID
AND    POH.BILL_TO_LOCATION_ID = HRLB.LOCATION_ID
AND    POH.AGENT_ID = PPF.PERSON_ID
AND    POH.SEGMENT1 = NVL (:PO_NUMBER, POH.SEGMENT1);    -- Enter Purchase Order Number