WITH t
                                                                       AS (SELECT  v_chr_sernum
                                                                                     AS in_cls
                                                                            INTO v_chr_sernumdata
                                                                             FROM DUAL),
                                                                       t1
                                                                       AS (    SELECT  DISTINCT
                                                                                      REGEXP_SUBSTR (
                                                                                         in_cls,
                                                                                         '[^,]+',
                                                                                         1,
                                                                                         ROWNUM)
                                                                                         names
                                                                                 FROM t
                                                                           CONNECT BY ROWNUM <=
                                                                                         LENGTH (
                                                                                            REGEXP_REPLACE (
                                                                                               in_cls,
                                                                                               '[^,]'))
                                                                                         + 1)
                                                                  SELECT RTRIM (
                                                                            XMLAGG (
                                                                               XMLELEMENT (
                                                                                  a,
                                                                                  names
                                                                                  || ',').EXTRACT (
                                                                                  '//text()')),
                                                                            ',')
                                                                            v_chr_sernumdata
                                                                    FROM t1;