refactored getRates

DRY!
instead of three times same code
if(xxx) {
	$tax_query = $this->db->query("SELECT tr2.tax_rate_id, tr2.name, tr2.rate, tr2.type, tr1.priority FROM " . DB_PREFIX . "tax_rule tr1 LEFT JOIN " . DB_PREFIX . "tax_rate tr2 ON (tr1.tax_rate_id = tr2.tax_rate_id) INNER JOIN " . DB_PREFIX . "tax_rate_to_customer_group tr2cg ON (tr2.tax_rate_id = tr2cg.tax_rate_id) LEFT JOIN " . DB_PREFIX . "zone_to_geo_zone z2gz ON (tr2.geo_zone_id = z2gz.geo_zone_id) LEFT JOIN " . DB_PREFIX . "geo_zone gz ON (tr2.geo_zone_id = gz.geo_zone_id) WHERE tr1.tax_class_id = '" . (int)$tax_class_id . "' AND tr1.based = 'xxxx' AND tr2cg.customer_group_id = '" . (int)$customer_group_id . "' AND z2gz.country_id = '" . (int)$this->store_address['country_id'] . "' AND (z2gz.zone_id = '0' OR z2gz.zone_id = '" . (int)$this->store_address['zone_id'] . "') ORDER BY tr1.priority ASC");

	foreach ($tax_query->rows as $result) {
		$tax_rates[$result['tax_rate_id']] = array(
			'tax_rate_id' => $result['tax_rate_id'],
			'name'        => $result['name'],
			'rate'        => $result['rate'],
			'type'        => $result['type'],
			'priority'    => $result['priority']
		);
	}
}

changed to small array and implode