PHP运用正则表达式获取字符串中的特定字符

1. [PHP]代码  

<?php
$db = new PDO("mysql:host=localhost;dbname=album", &#39;root&#39;, &#39;&#39;);
$db->query("set names gb2312");
$sql="SELECT * FROM `sales`";
$rows = $db->query($sql)->fetchall();
foreach($rows as $row)
{
$str  =  $row[&#39;detail&#39;];  
preg_match("/[".chr(0xa1)."-".chr(0xff)."]{4}市/",$str,$regs);  
echo $regs[0]?$regs[0]:&#39;暂无&#39;;
echo "<br>";
}
?>