create table v_EXAMPLE_L (
    nip number,
    xmlcontent clob
);

Insert into V_EXAMPLE_L (NIP,XMLCONTENT) 
values (17852,'<section><block><name>delta</name><content>548484646846484</content></block></section>');
Insert into V_EXAMPLE_L (NIP,XMLCONTENT) 
values (17852,'<section><block><name>omega</name><content>545648468484</content></block></section>');
Insert into V_EXAMPLE_L (NIP,XMLCONTENT) 
values (17852,
'<section><block><name>gamma</name><content>54564846qsdqsdqsdqsd8484</content></block></section>');

CREATE OR REPLACE function assemble_clob(p_deta number,p_omega number)
return clob
is
  v_clob clob;    
  cursor c2 is  select xmlcontent from V_EXAMPLE_L where NIP=17852 ;
begin

  for rec in c2   loop
    --v_clob := v_clob ||  XMLTYPE.getClobVal(rec.xmlcontent);     
    v_clob := v_clob ||  rec.xmlcontent;
  end loop;
  return (v_clob);
   --return   (dbms_xmlquery.getXml( dbms_xmlquery.set_context("Select 1 from dual"))   )
end assemble_clob;