CREATE OR REPLACE FUNCTION TCODE_NAME(code VARCHAR2, s_code VARCHAR2)
   RETURN VARCHAR2
IS
   code_name   VARCHAR2 (40);
BEGIN
   SELECT code_name
     INTO code_name
     FROM tcode
    WHERE code_lgroup = code AND code_mgroup = s_code;

   IF code_name = NULL OR code_name = ''
   THEN
      RETURN s_code;
   ELSE
      RETURN code_name;
   END IF;
END;