Помогите написать запрос на выборку штрихкодов : Oracle

 select smspec.article,smspec.quantity,barcode
 from smspec,SMStoreUnits where docid='0266' 
and doctype='WO'
and SMStoreUnits.article=smspec.article 
order by smspec.article

select t.article,t.quantity,
   (select barcode 
      from smstoreunits b 
      where b.article=t.article and rownum=1) barcode
  from smspec t 
  where docid='0266' 
    and doctype='WO'
  order by t.article

create or replace function barToStrcreate  ( p_a in varchar2 )
    return varchar2
    is
        l_str  varchar2(2000) default null;
        l_sep  varchar2(1) default null;
    begin
        for x in ( select barcode from smstoreunits where article = p_a ) loop
            l_str := l_str || l_sep || x.barcode;
           l_sep := ',';
       end loop;
       return l_str;
   end;

 select t.article,t.quantity,
   barToStrcreate(t.article) barcode
  from smspec t 
  where docid='0266' 
    and doctype='WO'
  order by t.article