PO Approval History - SQL Query

SELECT DISTINCT
  prh.creation_date req_creation_date,
  prh.segment1 req_number,
  gl.SEGMENT3 COST_CENTER,
  hp.full_name REQUESTOR,
  lp.full_name PREPARER_NAME,
  gl.SEGMENT1 COMPANY,
  cat.segment1 category,
  (prl.unit_price* prl.quantity) requisition_amount,
  prh.AUTHORIZATION_STATUS,
  poh.segment1 po_number,
  pv.vendor_name vendor,
  poh.AUTHORIZATION_STATUS PO_STATUS,
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 0
  ) ||' BY ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 0
  ) ||' -> ' ||
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 1
  ) ||' -> ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 1
  ) ||' -> ' ||
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 2
  ) ||' -> ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 2
  ) ||' -> ' ||
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 3
  ) ||' -> ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 3
  ) ||' -> ' ||
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 4
  ) ||' -> ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 4
  ) ||' -> ' ||
  (
    SELECT app.action_code
    FROM apps.PO_ACTION_HISTORY app
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.sequence_num        = 5
  ) ||' -> ' ||
  (
    SELECT DISTINCT per.full_name
    FROM apps.PO_ACTION_HISTORY app,
      apps.PER_PEOPLE_V7 per,
      apps.PER_ASSIGNMENTS_V7 dep
    WHERE prh.REQUISITION_HEADER_ID = app.object_id (+)
    AND app.employee_id         = per.person_id(+)
    AND per.person_id           = dep.person_id(+)
    AND sequence_num            = 5
  )
  APPROVAL_FLOW
FROM
  apps.PO_REQUISITION_HEADERS_ALL prh,
  apps.PO_REQUISITION_LINES_ALL prl,
  apps.PO_REQ_DISTRIBUTIONS_ALL prd,
  apps.per_all_people_f hp ,
  apps.per_all_people_f lp ,
  apps.po_distributions_all pod,
  apps.po_lines_all pol,
  apps.po_headers_all poh,
  apps.po_vendors pv,
  apps.GL_CODE_COMBINATIONS GL,
  apps.MTL_CATEGORIES CAT
WHERE
  prh.org_id     = 182
AND prh.segment1 = NVL(:REQ_NUMBER,prh.segment1)
AND prh.creation_date BETWEEN TRUNC(to_date(:P_FROM_DATE,
  'YYYY/MM/DD HH24:MI:SS')) AND TRUNC(to_date(:P_TO_DATE,
  'YYYY/MM/DD HH24:MI:SS'))
AND prh.preparer_id           = NVL(:CREATED_BY,prh.preparer_id)
AND prh.REQUISITION_HEADER_ID = prl.REQUISITION_HEADER_ID
AND prl.REQUISITION_LINE_ID   = prd.REQUISITION_LINE_ID
AND prh.preparer_id           = hp.person_id
AND prl.to_person_id          = lp.person_id
AND prd.distribution_id       = pod.req_distribution_id (+)
AND pod.po_line_id            = pol.po_line_id (+)
AND pod.PO_HEADER_ID          = poh.PO_HEADER_ID (+)
AND poh.vendor_id             = pv.vendor_id (+)
AND prd.code_combination_id   = gl.code_combination_id
AND prl.category_id           = cat.category_id
AND prh.AUTHORIZATION_STATUS <> 'SYSTEM_SAVED'
ORDER BY
  prh.creation_date;