public function как ограничить количество символов

public function getProductRelated($product_id) {
$product_data = array();

$query = $this->db->query("SELECT *, (p.product_id) AS related_id FROM
" . DB_PREFIX . "product_to_category p2c
LEFT JOIN " . DB_PREFIX . "product p ON (p2c.product_id = p.product_id)
LEFT JOIN " . DB_PREFIX . "product_to_store p2s ON (p.product_id = p2s.product_id)
WHERE
p2c.category_id IN (SELECT p2c2.category_id FROM " . DB_PREFIX . "product_to_category p2c2 WHERE p2c2.product_id = " . (int) $product_id . ")
AND p.product_id <> " . (int) $product_id . "
AND p.status = '1'
AND p.stock_status_id != '5'
AND p.date_available <= NOW()
AND p2s.store_id = '" . (int)$this->config->get('config_store_id') . "'
ORDER BY RAND() ASC
LIMIT 0,4");


foreach ($query->rows as $result) {
$product_data[$result['related_id']] = $this->getProduct($result['related_id']);
}

return $product_data;
}