В контрллере категории catalog\controller\product\category.php
Есть строка
$results = $this->model_catalog_product->getProducts($data);
Поэтому залазим в контроллер catalog\model\catalog\product.php и находим метод getProducts().
Там мы видим SQL запрос. Переписываем его.
$sql = "SELECT p.product_id, (SELECT AVG(rating) AS total FROM " . DB_PREFIX . "review r1 WHERE r1.product_id = p.product_id AND r1.status = '1' GROUP BY r1.product_id) AS rating, (SELECT COUNT(*) FROM " . DB_PREFIX . "product_related pr WHERE pr.product_id = p.product_id) AS related, (SELECT price FROM " . DB_PREFIX . "product_discount pd2 WHERE pd2.product_id = p.product_id AND pd2.customer_group_id = '" . (int)$customer_group_id . "' AND pd2.quantity = '1' AND ((pd2.date_start = '0000-00-00' OR pd2.date_start < NOW()) AND (pd2.date_end = '0000-00-00' OR pd2.date_end > NOW())) ORDER BY pd2.priority ASC, pd2.price ASC LIMIT 1) AS discount, (SELECT price FROM " . DB_PREFIX . "product_special ps WHERE ps.product_id = p.product_id AND ps.customer_group_id = '" . (int)$customer_group_id . "' AND ((ps.date_start = '0000-00-00' OR ps.date_start < NOW()) AND (ps.date_end = '0000-00-00' OR ps.date_end > NOW())) ORDER BY ps.priority ASC, ps.price ASC LIMIT 1) AS special";
Все... Дальше не интересно. В файле catalog\view\theme\ваш_шаблон\template\product\category.tpl теперь доступна переменная $product['related'], которая содержит числовое значение.
P.S. Сам не проверял.
UPDATED:
Кажется я фигню написал. Там ниже вызов в цикле:
foreach ($query->rows as $result) {
$product_data[$result['product_id']] = $this->getProduct($result['product_id']);
}
О, чудесный OpenCart! О, божественная архитектура!
Значит так... Забыли про getProducts. Вместо того, чтобы редактировать метод getProducts нужно редактировать getProduct по аналогии т.е.
$query = $this->db->query("SELECT DISTINCT *, pd.name AS name, p.image, m.name AS manufacturer, (SELECT price FROM " . DB_PREFIX . "product_discount pd2 WHERE pd2.product_id = p.product_id AND pd2.customer_group_id = '" . (int)$customer_group_id . "' AND pd2.quantity = '1' AND ((pd2.date_start = '0000-00-00' OR pd2.date_start < NOW()) AND (pd2.date_end = '0000-00-00' OR pd2.date_end > NOW())) ORDER BY pd2.priority ASC, pd2.price ASC LIMIT 1) AS discount, (SELECT COUNT(*) FROM " . DB_PREFIX . "product_related pr WHERE pr.product_id = p.product_id) AS related, (SELECT price FROM " . DB_PREFIX . "product_special ps WHERE ps.product_id = p.product_id AND ps.customer_group_id = '" . (int)$customer_group_id . "' AND ((ps.date_start = '0000-00-00' OR ps.date_start < NOW()) AND (ps.date_end = '0000-00-00' OR ps.date_end > NOW())) ORDER BY ps.priority ASC, ps.price ASC LIMIT 1) AS special, (SELECT points FROM " . DB_PREFIX . "product_reward pr WHERE pr.product_id = p.product_id AND customer_group_id = '" . (int)$customer_group_id . "') AS reward, (SELECT ss.name FROM " . DB_PREFIX . "stock_status ss WHERE ss.stock_status_id = p.stock_status_id AND ss.language_id = '" . (int)$this->config->get('config_language_id') . "') AS stock_status, (SELECT wcd.unit FROM " . DB_PREFIX . "weight_class_description wcd WHERE p.weight_class_id = wcd.weight_class_id AND wcd.language_id = '" . (int)$this->config->get('config_language_id') . "') AS weight_class, (SELECT lcd.unit FROM " . DB_PREFIX . "length_class_description lcd WHERE p.length_class_id = lcd.length_class_id AND lcd.language_id = '" . (int)$this->config->get('config_language_id') . "') AS length_class, (SELECT AVG(rating) AS total FROM " . DB_PREFIX . "review r1 WHERE r1.product_id = p.product_id AND r1.status = '1' GROUP BY r1.product_id) AS rating, (SELECT COUNT(*) AS total FROM " . DB_PREFIX . "review r2 WHERE r2.product_id = p.product_id AND r2.status = '1' GROUP BY r2.product_id) AS reviews, p.sort_order FROM " . DB_PREFIX . "product p LEFT JOIN " . DB_PREFIX . "product_description pd ON (p.product_id = pd.product_id) LEFT JOIN " . DB_PREFIX . "product_to_store p2s ON (p.product_id = p2s.product_id) LEFT JOIN " . DB_PREFIX . "manufacturer m ON (p.manufacturer_id = m.manufacturer_id) WHERE p.product_id = '" . (int)$product_id . "' AND pd.language_id = '" . (int)$this->config->get('config_language_id') . "' AND p.status = '1' AND p.date_available <= NOW() AND p2s.store_id = '" . (int)$this->config->get('config_store_id') . "'");
UPDATE 2:
В этом прекрасном полотне надо добавить
if ($query->num_rows) {
return array(
'product_id' => $query->row['product_id'],
'related' => $query->row['related'], // вот это добавлено
'name' => $query->row['name'],
'description' => $query->row['description'],
'meta_description' => $query->row['meta_description'],
'meta_keyword' => $query->row['meta_keyword'],
'tag' => $query->row['tag'],
'model' => $query->row['model'],
'sku' => $query->row['sku'],
'upc' => $query->row['upc'],
'ean' => $query->row['ean'],
'jan' => $query->row['jan'],
'isbn' => $query->row['isbn'],
'mpn' => $query->row['mpn'],
'location' => $query->row['location'],
'quantity' => $query->row['quantity'],
'stock_status' => $query->row['stock_status'],
'image' => $query->row['image'],
'manufacturer_id' => $query->row['manufacturer_id'],
'manufacturer' => $query->row['manufacturer'],
'price' => ($query->row['discount'] ? $query->row['discount'] : $query->row['price']),
'special' => $query->row['special'],
'reward' => $query->row['reward'],
'points' => $query->row['points'],
'tax_class_id' => $query->row['tax_class_id'],
'date_available' => $query->row['date_available'],
'weight' => $query->row['weight'],
'weight_class_id' => $query->row['weight_class_id'],
'length' => $query->row['length'],
'width' => $query->row['width'],
'height' => $query->row['height'],
'length_class_id' => $query->row['length_class_id'],
'subtract' => $query->row['subtract'],
'rating' => round($query->row['rating']),
'reviews' => $query->row['reviews'] ? $query->row['reviews'] : 0,
'minimum' => $query->row['minimum'],
'sort_order' => $query->row['sort_order'],
'status' => $query->row['status'],
'date_added' => $query->row['date_added'],
'date_modified' => $query->row['date_modified'],
'viewed' => $query->row['viewed']
);