SELECT
  E1.EMP_CODE AS CODE
  , E1.EMP_LAST_NAME AS SURNAME
  , E1.EMP_FIRST_NAME AS NAME 
FROM
  (SELECT * FROM EMP WHERE VALID_FLG = '1') AS E1 JOIN (SELECT * FROM EMP WHERE VALID_FLG = '1') AS E2
    ON ( 
      replace (E1.EMP_LAST_NAME, ' ', '') = E2.EMP_LAST_NAME 
      AND replace (E1.EMP_FIRST_NAME, ' ', '') = E2.EMP_FIRST_NAME 
      AND E1.EMP_CODE != E2.EMP_CODE
    ) 
    OR ( 
      E1.EMP_LAST_NAME = replace (E2.EMP_LAST_NAME, ' ', '') 
      AND E1.EMP_FIRST_NAME = replace (E2.EMP_FIRST_NAME, ' ', '') 
      AND E1.EMP_CODE != E2.EMP_CODE
    ) 
ORDER BY
  replace (E1.EMP_LAST_NAME, ' ', '')
  , replace (E1.EMP_FIRST_NAME, ' ', '')
  , E1.EMP_CODE;