create table xmltab of xmltype

declare 
  l_cur sys_Refcursor; 
  l_ctx        number; 
  l_xml        xmltype; 
begin 
  open l_cur for  
    select ' '  as col from dual union all 
    select '  a  ' from dual union all 
    select ' a ' from dual union all 
    select '  ' from dual union all 
    select cast(null as varchar2(2)) from dual; 
 
    l_ctx := dbms_xmlgen.newContext(l_cur); 
    dbms_xmlgen.setNullHandling(l_ctx, dbms_xmlgen.NULL_ATTR); 
    dbms_xmlgen.setMaxRows(l_ctx, 100);    
    l_xml := dbms_xmlgen.getxmltype(l_ctx); 
    dbms_output.put_line(l_xml.getClobVal()); 
    insert into xmltab values (l_xml); 
    select * into l_xml from xmltab; 
    dbms_output.put_line(l_xml.getClobVal()); 
    rollback; 
end; 

drop  table xmltab