从HTML输入将数据保存到数据库

It's been a long time since my last question. I have a HTML user interface with an input from a user and I would like to insert this input into database. It doesn't work and I don't know why... I have used a lot of hints from here, but still nothing.

<form action = ".\addProduct.php" method="post">
    <div id="AddProduct" class = "w3-container list w3-animate-left">
        <h2>Add Product</h2>
        ID: <br>
        <input type = "text" name = "ID"/><br>
        CName: <br>
        <input type = "text" name = "CName"/><br>
        <br>
        <input type = "submit" value = "Add"/><br>
    </div>
</form>

<?php
// MY PHP CODE
if(isset($_REQUEST['Add'])) {
    $SQL = "USE sales;"
    $SQL = "INSERT INTO customers(ID, CName) values('" . $_POST["ID"] . "', '". $_POST["CName"] . "')";
    $result = mysql_query($SQL);
}
?>

Use mysqli instead of mysql. Also sanitize the user input before you input them to the database.

<form action = "addProduct.php" method="post">
<div id="AddProduct" class = "w3-container list w3-animate-left">
    <h2>Add Product</h2>
        ID: <br>
        <input type = "text" name = "ID"/><br>
        CName: <br>
        <input type = "text" name = "cName"/><br>
        <br>
        <input type = "submit" name = "Add" value = "Add"/><br>
</div>
</form>



<?php
if(isset($_POST['Add']))
{
$cID = $_POST['ID'];
$cName = $_POST['cName'];

$SQL = "INSERT INTO customers(ID, CName) values('$cID', '$cName')";

$result = mysqli_query($conn,$SQL);
}
?>