我的第二行php代码之接受get请求连接数据库实现登录验证

<?php
$conn = mysql_connect("localhost","root","") or die("failed to connect db");
mysql_select_db("lio", $conn) or die ("failed to select db");
//mysql_query("SET NAMES 'UTF8'",$conn);
$username=$_GET['user'];
$passwd=$_GET['passwd'];
$sql = "select * from userinfo where user='$username' and passwd='$passwd'";
$Result = mysql_query($sql, $conn);
$onerow = mysql_fetch_array($Result);

if ($onerow )
    echo "正确";
else
    echo "错误";
?>