I'm trying to add data to my database but it won't work, and no error message is displayed.

**order.php:**

```
<?php   

$con=mysqli_connect("localhost","root","","jutta");

//if form is submitted
if(isset($_POST['submit'])) { 
    $size=$_POST['shoe_sizes'];
    $qan=$_POST['quantity'];
    $details=$_POST['shipping_address'];
    $contact=$_POST['contact'];
    $date=date('Y-m-d');

    $sql="INSERT INTO orders(size, qan, address, contact, date) VALUES ($size, '$qan', '$address', '$contact', '$date')";

    $query=mysqli_query($con, $sql) or die('Query could not be connected.');

    if($query) {
        echo "success";
    }
    else {
        echo "fail.";
    }
}
?>

```

**My form:**

```
<form action='order.php' method='post'>
    <br>
    <a href='admin/product_images/$pro_image' title='$pro_title' class='MagicZoom'>
    <img src='admin/product_images/$pro_image' width='200' height='150' class='img-responsive'/></a><br>
    Name: <font style='color:#2E9AFE; text-align: center;'><b>$pro_title </b></font>
    <p><label>Price:</label> <font style='color:black; text-align: center;'><b> Rs. $pro_price </b></font></p>
    <div class='row'>
        <div class='col-sm-6'>
            <b><label>Select Size:</label> </b><select name='shoe_sizes'>
                    <option>5</option>
                    <option>6</option>
                    <option>7</option>
                    <option>8</option>
                    <option>9</option>
                </select>
                </div>
                <div class='col-sm-6'>
                <b><label>Quantity:</label> </b><select name='quantity'>
                    <option>1</option>
                    <option>2</option>
                    <option>3</option>
                    <option>4</option>
                </select></div>
        </div><hr>
    <b style='color: grey;'><label>Shipping Address: <br></b><textarea name='shipping_address' cols='25' rows='3' required /></textarea><br>
    <b><label>Contact No. :</label></b> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input name='contact' type='tel' id='phone' placeholder='Your Contact Number'>
    <hr>
    <button type='submit' name='submit' class='btn btn-primary'><a href='order.php' style='color:white; text-decoration:none;'>Order Now</a></button>
</form>

```

It redirects me to `order.php` file without inserting data to datbase and not even any message just a blank page.