Sql SYSDATE的时间括号

我需要选择时间戳介于现在和过去5分钟之间的行。我该怎么做？诸如此类：

select * from tableName where timestamp between sysdate and up to -5 min

越简单越好

select *
  from tableName
 where timestamp between sysdate and sysdate - interval '5' minute

或旧式：

select *
  from tableName
 where timestamp between sysdate and sysdate - 5 * 60 / 86400

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') NOW
,           to_char(sysdate - 1/24/12,'yyyy-mm-dd hh24:mi:ss') "5 min. before"
    from dual;

NOW                 5 min. before
------------------- -------------------
2011-09-15 15:11:06 2011-09-15 15:06:06