opencart - 如何将扩展从 OpenCart 1.5 转换（重新编码）到 2.3

Question

我曾经为 OpenCart 1.5 做了几个扩展，我想将它们“转换”为 OpenCart 2.3.0.2。

我很难弄清楚如何为 2.3.0.2 执行以下操作：

    echo "Free Items Disabler started.<br>";
    $sqll = "SELECT * FROM " . DB_PREFIX . "product p LEFT JOIN " . DB_PREFIX . "product_description pd ON (p.product_id = pd.product_id) WHERE pd.language_id = '" . (int)$this->config->get('config_language_id') . "'";

    $result = mysql_query($sqll)or die(mysql_error());
    $antall = mysql_num_rows($result);
    echo "Products to check: ".$antall."<br>";
 ... 
$this->session->data['success'] = 'Free Items Disabler has
 disabled ' . $products_changed . ' products with no price!';

• 如何将消息打印到页面？回声不会出现在任何地方。
• 如何计算查询结果？当我尝试时，页面总是停止工作。

我已经尝试查看其他 2.3 扩展来解决这个问题，但我找不到任何类似的东西。我花了两天时间试图弄清楚这一点。

Answer 1

解决方案原来是：

$query = $this->db->query("SELECT * FROM " . DB_PREFIX . "product p LEFT JOIN " . DB_PREFIX . "product_description pd ON (p.product_id = pd.product_id) ");
$num = $query->rows;
...
$this->session->data['success'] = 'Free Items Disabler has disabled ' . $products_changed . ' products with no price!';