php随机取mysql记录方法示例

select * from tablename order by rand() limit 1

$query= "SELECT count(*) as count FROM recommends"; 
.... 
$max_num = $row['count']; // 取记录总数 
srand((double)microtime()*1000000); // 随机数种子 
$se_pos = rand(0, $max_num); // 随机数范围 
$length = 6; // 记录条数 
if (($max_num - $se_pos) <= $length) { 
$se_pos = $max_num - $se_pos; // 记录数不足6条的情况 
}
$query = "SELECT * FROM recommendsn limit ".$se_pos.",".$length;

<?php
$db = mysql_connect("localhost", "root");
mysql_select_db("xyj", $db);
$result = mysql_query("SELECT * FROM obj", $db);
$max_num = mysql_num_rows($result); //取得数据库的记录数
srand((double)microtime() * 10000000); //生成随机数种子。
$se_pos = rand(0, $max_num - 1); //从0到最大记录数取随机数
$length = 30; //设定共取多少条记录
//下面是取出指定数目的记录。
$result_lim = mysql_query("select * from obj limit $se_pos,$length", $db);
$myrow_lim = mysql_fetch_array($result_lim);
printf("%sn", $se_pos); //显示随机得到的记录号
printf("%sn", $myrow_lim["name"]); //显示随机得到的记录的name字段