Purchase Order Status Report

SELECT 
  po.PO_NUMBER,
  po.CREATION_DATE,
  po.LAST_UPDATE_DATE,
  v.VENDOR_NAME,
  v.VENDOR_NUMBER,
  vs.VENDOR_SITE_CODE,
  po.TOTAL_AMOUNT,
  po.CURRENCY_CODE,
  po.AUTHORIZATION_STATUS,
  po.APPROVED_DATE,
  po.APPROVED_BY,
  po.CLOSED_DATE,
  po.CANCEL_FLAG,
  u.USER_NAME AS CREATED_BY,
  u.DESCRIPTION AS CREATED_BY_NAME,
  bu.BU_NAME,
  po.COMMENTS,
  po.TERMS_ID,
  po.SHIP_TO_LOCATION_ID,
  po.BILL_TO_LOCATION_ID,
  COUNT(pol.LINE_NUM) AS LINE_COUNT,
  SUM(pol.QUANTITY) AS TOTAL_QUANTITY,
  SUM(pol.AMOUNT) AS TOTAL_LINE_AMOUNT
FROM PO_HEADERS_ALL po
JOIN AP_VENDORS v ON po.VENDOR_ID = v.VENDOR_ID
JOIN AP_VENDOR_SITES_ALL vs ON po.VENDOR_SITE_ID = vs.VENDOR_SITE_ID
JOIN FND_USER u ON po.CREATED_BY = u.USER_ID
JOIN HR_BUSINESS_UNITS bu ON po.PRC_BU_ID = bu.BU_ID
LEFT JOIN PO_LINES_ALL pol ON po.PO_HEADER_ID = pol.PO_HEADER_ID
WHERE po.CREATION_DATE >= :start_date
  AND (:end_date IS NULL OR po.CREATION_DATE <= :end_date)
  AND (:vendor_id IS NULL OR po.VENDOR_ID = :vendor_id)
  AND (:authorization_status IS NULL OR po.AUTHORIZATION_STATUS = :authorization_status)
  AND (:bu_id IS NULL OR po.PRC_BU_ID = :bu_id)
  AND po.CANCEL_FLAG = 'N'
GROUP BY po.PO_NUMBER, po.CREATION_DATE, po.LAST_UPDATE_DATE, v.VENDOR_NAME, v.VENDOR_NUMBER,
         vs.VENDOR_SITE_CODE, po.TOTAL_AMOUNT, po.CURRENCY_CODE, po.AUTHORIZATION_STATUS,
         po.APPROVED_DATE, po.APPROVED_BY, po.CLOSED_DATE, po.CANCEL_FLAG, u.USER_NAME,
         u.DESCRIPTION, bu.BU_NAME, po.COMMENTS, po.TERMS_ID, po.SHIP_TO_LOCATION_ID,
         po.BILL_TO_LOCATION_ID
ORDER BY po.CREATION_DATE DESC, po.PO_NUMBER