declare
  TYPE RefCurType IS REF CURSOR;
  cv RefCurType;
  sql_str varchar2( 2000 );
  param varchar2( 1 ) := 'X';
  rnum number;
begin
  sql_str := 'select (select 555 from sys.dual) from sys.dual where dummy = :b1 ';
  open cv for sql_str using param;
  loop
    fetch cv into rnum;
    exit when cv%notfound;
    DBMS_OUTPUT.PUT_LINE ( 'rnum= ' || rnum );     
  end loop;    
  close cv; 
end;

select a.t$ttyp as ttyp, sum (t$amth + t$cdam)
  from baan.ttfacr200308 a,
       baan.ttfacr200308 b
 where trim (a.t$cuno) = trim (a.cuno) 
   and a.t$docd < a.date_t
   and b.t$ttyp = a.t$ttyp
   and b.t$trec <> a.t$trec
   and t$docd < date_f
 group by a.t$ttyp