数据库不能插入数据，紧急求助

<?php
$con=mysql_connect("localhost","root","liuzhiyang");
mysql_select_db("liwu");
$username=$_POST["username"];
$email=$_POST["email"];
$number=$_POST["number"];
$people=$_POST["people"];
$radio=$_POST["radio"];
$sqery="insert into $mingdan (username,email,number,radio,people) values('$username','$email','$number','radio','$people')";
$result=mysql_query("$sqery",$con);
mysql_close($con);
?>

应该是没有指定编码吧，可以参考下
http://www.phpfans.net/bbs/viewt ... &extra=page%3D1