insert into e_rel_customer(
CUSTOM_ID   
,REL_CUSTOM_ID   
,REL_ID   
,CUSTOM_NAME   
,idtype_id   
)
SELECT T1.MFCUSTOMERID AS CUSTOMERID,
       T2.MFCUSTOMERID AS RELATIVEID,
       RELATIONSHIP,
       CUSTOMERNAME,
       CERTTYPE
  FROM XD_CUSTOMER_RELATIVE,
  LEFT JOIN (SELECT NVL(MAX(MFCUSTOMERID), '') MFCUSTOMERID, CUSTOMERID
               FROM SOR_XD_CUSTOMER_INFO
              WHERE MFCUSTOMERID IS NOT NULL
              GROUP BY CUSTOMERID) T1
       ON T1.CUSTOMERID = XD_CUSTOMER_RELATIVE.CUSTOMERID
  LEFT JOIN (SELECT NVL(MAX(MFCUSTOMERID), '') MFCUSTOMERID, CUSTOMERID
               FROM SOR_XD_CUSTOMER_INFO
              WHERE MFCUSTOMERID IS NOT NULL
              GROUP BY CUSTOMERID) T2
       ON T2.CUSTOMERID = XD_CUSTOMER_RELATIVE.RELATIVEID