Declare

  v_ival number;
  i number;
Begin
  --Loop循环
  v_ival := 0;
  loop
    exit when v_ival > 3; --循环体
    v_ival := v_ival + 1;
    dbms_output.put_line('loop循环:' || v_ival);
  end loop;
  --While循环
  v_ival := 0;
  while v_ival < 4 loop --循环体
    v_ival := v_ival + 1;
    dbms_output.put_line('while循环:' || v_ival);
  end loop;
  --For循环
  for v_count in reverse 0 .. 4 loop   --reverse递减
    dbms_output.put_line('for循环:' || v_count);
  end loop;
   for t in 1..10 loop
    i:=i+t;
    dbms_output.put_line('for循环t:' || t);
  end loop;
END;