Query to Get Requisition creator name and Po creator name in oracle fusion

 1-To get requisition creator name 

 SELECT spn.display_name  req_creator_name

          FROM per_person_names_f_v spn

         WHERE     POR_REQUISITION_HEADERS_ALL.preparer_id = spn.PERSON_ID(+)

               AND TRUNC (SYSDATE) BETWEEN spn.EFFECTIVE_START_DATE(+)

                                       AND spn.EFFECTIVE_END_DATE(+)

2- To get PO creator name 

SELECT spn.display_name po_creator_name

  FROM per_person_names_f_v spn

 WHERE     po_headers_all.AGENT_ID = spn.PERSON_ID(+)

       AND TRUNC (SYSDATE) BETWEEN spn.EFFECTIVE_START_DATE(+)

                               AND spn.EFFECTIVE_END_DATE(+)