Thinkphp3.2.3查询24小时之内的数据条件

/计算24小时之内的时间戳
$startime = time();
$endtime = $startime + 86399;
$where =array();
//拼接查询条件方法一
$where['b.a_time'] = array('between',array($startime,$endtime));
$where['a.u_id'] = $id;
$where['a.is_read'] = 0;
//方法二
//$where['b.a_time']=array('between',"startime,endtime");
//$activityone = M('joinactivity as a')->join('fh_activity as b on b.a_id = a.a_id')->where(array('a.u_id'=>$id,'a.is_read'=>0))->field('b.a_title, b.a_time, a.ja_addtime')->order('a.ja_addtime DESC')->find();
$activityone = M('joinactivity as a')->join('fh_activity as b on b.a_id = a.a_id')->where($where)->field('b.a_title, b.a_time, a.ja_addtime')->order('a.ja_addtime DESC')->find();
$num = M('joinactivity as a')->join('fh_activity as b on b.a_id = a.a_id')->where($where)->count();