Oracle 11i  pl/sql

Try this:

http://www.experts-exchange.com/Database/Oracle/Q_24914739.html?#a25864822

SELECT
       RTRIM(
           EXTRACT(XMLAGG(XMLELEMENT("s", yourtable.column3 || '||')), '/s/text()').getstringval(),
           '||'
       )
           column3
FROM yourtable
;

I keep getting an error on this (I had tried to use the listagg function as well - but same error)  Keeps telling me I am missing left parenthesis but I must be blind because I cannots ee what i am missing:

SELECT
       RTRIM(
           EXTRACT(XMLAGG(XMLELEMENT("s", dossier_waste_packaging dwp.dwp.packaging_types || '||')), '/s/text()').getstringval(),
           '||'
       )
           dwp.packaging_types
FROM dossier_waste_packaging dwp
      WHERE dwp.dos_hwmd_sys_entered_yr = 10
      AND dwp.dossier_identifier = 325
      AND dwp.dossier_type_code = 'EXP';

I tried this as well:

SELECT DISTINCT LISTAGG(dwp.packaging_types, '||') WITHIN GROUP AS PackagingList
      FROM dossier_waste_packaging dwp
      WHERE dwp.dos_hwmd_sys_entered_yr = 10
      AND dwp.dossier_identifier = 325
      AND dwp.dossier_type_code = 'EXP