帝国CMS批量修改信息时间

$sql=$empire->query("select * from {$dbtbpre}ecms_news_index");
while($r=$empire->fetch($sql)){
$donewstime=time()-rand(300,600);  //上线时间 当前时间+300-600是秒自己换算
$empire->query("update {$dbtbpre}ecms_news_index set newstime='$donewstime' where id='$r[id]'");
$empire->query("update {$dbtbpre}ecms_news set newstime='$donewstime' where id='$r[id]'");
}