Oracle中loop语句的使用

set serveroutput on
declare
  num int;
  total int;
begin
  num:=0;
  total:=0;
  loop 
    num:=num+1;
    total:=total+num;
    exit when num=5;
  end loop;
  dbms_output.put_line('前5个自然数的和是'||total);
end;