在SQL中实现黑客新闻排序算法

  SELECT x.*
    FROM POSTS x
    JOIN (SELECT p.postid, 
                 SUM(v.vote) AS points
            FROM POSTS p
            JOIN VOTES v ON v.postid = p.postid
        GROUP BY p.postid) y ON y.postid = x.postid
ORDER BY (y.points - 1)/POW(((UNIX_TIMESTAMP(NOW()) - UNIX_TIMESTAMP(x.timestamp))/3600)+2, 1.5) DESC
   LIMIT n

$sql=mysql_query("SELECT * FROM news 
                         ORDER BY ((noOfLike-1)/POW(((UNIX_TIMESTAMP(NOW()) - 
                         UNIX_TIMESTAMP(created_at))/3600)+2,1.5)) DESC 
                 LIMIT 20");