INPUT RADIO – does not transmit value to database

I post code. For some reason, the radio buttons do not transmit values ​​in the database. Tell me what is the problem.

if (empty($_POST))
{
?>
    <form action="invite.php" method="post">
<b> &nbsp;</b><br />
</div>
<input type="text" name="login"  /></div>
<b></b></div>
<input type="password" name="password"  />
            </div>
  <input type="radio" value="j" name="food">  <input type="radio" value="d" name="food">
 </div>
   <input type="radio" name="nofoot" value="2">
 </div>
<input type="submit" value="" >
</div>
    </form>
    <?php
}
else
{
    $login = (isset($_POST['login'])) ? mysql_real_escape_string($_POST['login']) : '';
    $password = (isset($_POST['password'])) ? mysql_real_escape_string($_POST['password']) : '';
    $nofood = (isset($_POST['nofood'])) ? mysql_real_escape_string($_POST['nofood']) : '';
    $food = (isset($_POST['food'])) ? mysql_real_escape_string($_POST['food']) : '';
    $error = false;
    $errort = '';
    if (strlen($login) < 2)
    {
        $error = true;
        $errort .= '    e-mail';
    }
    if (strlen($password) < 6)
    {
        $error = true;
        $errort .= '     6 ';
    }
    $query = "SELECT `id`
                FROM `users`
                WHERE `login`='{$login}'
                LIMIT 1";
    $sql = mysql_query($query) or die(mysql_error());
    if (mysql_num_rows($sql)==1)
    {
        $error = true;
        $errort .= '     . .';
    }
    if (!$error)
    {
        $salt = GenerateSalt();
        $hashed_password = md5(md5($password) . $salt);
        $query = "INSERT
                    INTO `users`
                    SET
                        `login`='{$login}',
                        `city`='{$city}',
                        `password`='{$hashed_password}',
                        `salt`='{$salt}'";
        $sql = mysql_query($query) or die(mysql_error());
        print '<h4>,   !</h4><a href="login.php"></a>';
    }
    else
    {
        print '<h4>  </h4>' . $errort;
    }
}

Answer 1, Authority 100%

Try to specify the same names from the buttons, but only with different values ​​

:<input type="radio" value="yfood" name="food">
 :<input type="radio" value="nfood" name="food">
....
$food = (isset($_POST['food']) ? mysql_real_escape_string($_POST['food']) : "";
...
mysql_insert("INSERT INTO `users` SET `food` = '".$food."' ");

Yes, and in general, I did not notice in your code to transmitted data from $ FOOD in the database