Zen-cart产品页面显示星星评论代码

在zen-cart二次开发过程中，如何在zen-cart产品页面显示评论星星代码，博主摘录如下：
[php]
$count_stars_query = "select count(reviews_rating) as num, avg(reviews_rating) as aver from " . TABLE_REVIEWS . " where products_id = ‘" . (int)$_GET[‘products_id’] . "’";
$count_stars = $db->Execute($count_stars_query);
$starnum = round($count_stars->fields[‘aver’]);
$star = array("stars_1.gif","stars_2.gif","stars_3.gif","stars_4.gif","stars_5.gif");
if($count_stars->fields[‘num’]>=1){
$reviews_display ='<br />’.$count_stars->fields[‘num’].’ reviews<br><img src="includes/templates/模板/images/’. $star[$starnum-1] .’" />’;
}else{
$reviews_display ='<br />0 reviews<br><img src="includes/templates/模板/images/stars_0.gif" />’;
}
echo $reviews_display;
[/php]
将这段代码放到产品页面页面（/includes/templates/模板名称/templates/product_info.php）价格下面，样式可以自己调试，确定stars_0.gif的存在。