login and password not working

hi all i have a login form with user name and password. The user name field is called "user_name" and password field is called "password".
I have applied the code.
I m filing the right user and password.
In the database i have user_id, user_name, password.
neither an error is coming nor its redirectig it.

Code:

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require_once("../config.php");

$msg="";
if(isset($_REQUEST['id']))
{
$id=$_REQUEST['id'];
$qry="select * from admin_table where user_id='$id'";
$result=mysql_query($qry);
$row=mysql_fetch_array($result);


}

if(isset($_REQUEST['submit']))
{

        $user_name=$_REQUEST['user_name'];
        $password=$_REQUEST['password'];

        $qry="select * from admin_table WHERE user_name='$user_name' and password='$password'";
        //echo $qry;
       
        $result=mysql_query($qry);
       
        if(mysql_num_rows($result)>0)
        {
       
                if(($user_name==$row['user_name']) && ($password==$row['password']))
               
                {
                        header("Location: control_panel.php");
                }
                else
                {
                $msg="Login ID or password is incorrect";
                }
        }
}

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It's your responsibility to die().

You can never see error, since you're not instructing the code to show any:

Code:

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$result=mysql_query($qry) or die(mysql_error());

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