大侠们：下面的程序运行时总提示这样的错误：
Warning: mssql_query() [function.mssql-query]: message: 'date' 不是可以识别的 函数名。 (severity 15) in F:\guest\sub_guest.php on line 20
Warning: mssql_query() [function.mssql-query]: Query failed in F:\guest\sub_guest.php on line 20
帮忙看一下，谢谢
<?php session_start();?>
<?php
$conn=mssql_connect("WWW-LIUWEI","","") or die("数据库连接错误！");
mssql_select_db("guest",$conn);
function unhtml($content)
{
$content=htmlspecialchars($content);
$content=str_replace(chr(13)," <br>",$content);
$content=str_replace(chr(13)," ",$content);
$content=str_replace(chr(13)," ",$content);
return trim($content);
}
$title=$_POST[title];
$content=$_POST[content];
$username=$_POST[username];
$sql="insert into guest(guest_title,guest_content,guest_username,submit_date)values('$title','$content','$username',date('Y-m-d'))";
$query=mssql_query($sql,$conn);?>
<script language="javascript">
window.alert(" <?php echo "留言成功！"?>");
window.opener.parent.location="index.php";
window.close();
