這個首頁四格怎麼改為 Top 15 呢？

引用:

//今日發貼排行
$tomonth=date(n);
$todate=date(j);
$toyear=date(Y);
$time=mktime(0,0,0,$tomonth,$todate,$toyear);
$query=$db->query("select count(pid) as num,authorid,author from $tablepre"."posts where dateline>=$time group by authorid order by num desc limit 0,10");
while($result=$db->fetch_array($query)){
$poststar.="<a href=space.php?uid=".$result[authorid].">".cutstr($result[author],8)."</a><font color=red>[".$result[num]."]</font>";
}