SQL & PL/SQL

hi,

I have a table like MYTABLE   (doc   xmltype)

I have to write a pl sql where I want to concat two xmltype element and insert the result in the table

declare

ONE        xmltype;

TWO        xmltype;

RES        xmltype;

begin

select xmlelement(....

        xmlelement(...

        xmlelement(...

        into ONE

        from ;

select xmlelement(....

        xmlelement(...

        into TWO

        from ;

  -- how can I concat ONE and TWO into RES ?

  insert into MYTABLE values (RES);

end;

/

thanks in advance!

Mark