按月过滤数据Mysql

Question

    $listSQL = "SELECT op.name as prodname,count(*) total 
                FROM oc_order_product op 
                INNER JOIN oc_order o ON op.order_id = o.order_id 
                INNER JOIN oc_product_to_category p2c ON op.product_id = p2c.product_id 
                INNER JOIN oc_category_description cd ON cd.category_id = p2c.category_id ";
    $listSQL = $listSQL."where lower(cd.name) LIKE '%".$category_name."%' 
                         AND YEAR(o.date_added) = '".$StartDate."' 
                         AND o.order_status_id > '0' ";
    $listSQL = $listSQL."GROUP BY op.name ORDER BY o.date_added ASC";

我有一个显示产品名称和按年计数的查询。

我想要显示产品名称，对于每个产品，显示月份和该特定年份该月份的计数。

以2015年为例，显示所有12个月，并显示该月的产品数量。

谢谢

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