大家来看这段代码，如何插不进数据库

大家来看这段代码，怎么插不进数据库
include("db.php");
if(!empty($_POST['sub'])){
$title=$_POST['title'];
$con=$_POST['non'];
$sql="insert into `test` (`id`,`title`,`non`,`date`) VALUES('null','$title','$con',now())";
mysql_query($sql);
echo "插入成功";
 }
 
?>

PHP code

$sql="insert into `test` (`title`,`non`,`date`) VALUES('$title','$con', now())"; <div class="clear">
                 
              
              
        
            </div>

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