oralceカスタム関数、複数のレコード値の組合せ文字列を返す

create or replace function fun_getorderproducterpcodes(v_ordersysno number) --          
return varchar2 is
v_all varchar2(1000);
begin
   DECLARE
     v_medCode VARCHAR2 (100);  
    CURSOR D_cursor IS
       select p.erpcode from  SoOrderItem t
       inner join PdProduct  p
       on p.sysno=t.productsysno
       where  t.ordersysno=v_ordersysno
       order by t.ProductSysNo asc;
     BEGIN
       OPEN D_cursor;
     loop
     fetch D_cursor into v_medCode;
     EXIT WHEN D_cursor%NOTFOUND;
     if length(v_all) > 0 THEN
        v_all := v_all ||','|| v_medCode;
     ELSE
        v_all := v_all || v_medCode;
     END IF;
    END LOOP;
    close D_cursor;
    end;
  return v_all;
end;