Insert in MySQL does not work and there is no error

I'm trying to insert products information into the database, but I must be missing something. It does not insert anything into the database, it's not even showing any errors.

Whats wrong with my code?

<?php 

    if(!empty($product_name)){
        if(!empty($product_category)){

        ////////////////////////////////////////////////
        ///// connect to database
        ////////////////////////////////////////////////

        $dbc = new mysqli("localhost", "root", "password", "table");

        // Check connection
        if (mysqli_connect_errno($dbc)) {
            echo "Failed to connect to MySQL: " . mysqli_connect_error();
        }

        if (isset($_POST['product_name'])) {

            $pid = ($_POST['thisID']);
            $product_name = ($_POST['product_name']);
            $product_category = ($_POST['product_category']);
            $product_detail = ($_POST['product_detail']);
            $product_price = ($_POST['product_price']);
            $product_company = ($_POST['product_company']);

            $query = "INSERT INTO product (product_name, product_category, product_price, product_detail,product_detail, product_company)
                VALUES ( '$product_name','$product_category','$product_price','$product_detail','$product_company')";

            $result= $this->mysqli->query($query) or die(mysqli_connect_errno()."Data cannot inserted");

            if($result){
                header('location:cp_product.php');
            }

            mysqli_close($dbc);
        }
    }}

?>

---

In your query you have add the product_detail column two times,there should be one ,as five columns refers to 5 values

product_detail,product_detail,

INSERT INTO product (product_name, product_category, product_price, product_detail, product_company)
VALUES ( '$product_name','$product_category','$product_price','$product_detail','$product_company');