How to use QueryBuilder in the method getTotalProducts of the class model/catalog/product of Opencart 3.0.3.2

[mauphung]

Please show me how to use QueryBuilder in the method getTotalProducts of the class model/catalog/product of Opencart 3.0.3.2
Code in the file model/catalog/product.php
public function getTotalProducts($data = array()) {

$sql = "SELECT COUNT(DISTINCT p.product_id) AS total";

if (!empty($data['filter_category_id'])) {
if (!empty($data['filter_sub_category'])) {
$sql .= " FROM " . DB_PREFIX . "category_path cp LEFT JOIN " .
DB_PREFIX . "product_to_category p2c ON (cp.category_id = p2c.category_id)";
} else {
$sql .= " FROM " . DB_PREFIX . "product_to_category p2c";
}

if (!empty($data['filter_filter'])) {
	$sql .= " LEFT JOIN " . 
		DB_PREFIX . "product_filter pf ON (p2c.product_id = pf.product_id) LEFT JOIN " . 
		DB_PREFIX . "product p ON (pf.product_id = p.product_id)";
} else {
	$sql .= " LEFT JOIN " . DB_PREFIX . "product p ON (p2c.product_id = p.product_id)";
		}

} else {
$sql .= " FROM " . DB_PREFIX . "product p";
}

...
Thank you very much in advance.
Mau