我有如下select语句和示例输出：-

select uph.creation_date, p.name,p.product_id from product p 
                left join user_product_history uph on p.product_id = uph.product_id 
                where uph.user_id = 124 order by uph.creation_date desc

如何按产品id和最新创建日期分组？请帮忙。谢谢您。
用php api.model文件编辑

// ~/user/product_history
    public function product_history($data) {
        $sql = 'select uph.creation_date,
        p.name,
        p.product_id
        from product p
        join user_product_history uph
        on p.product_id = uph.product_id and
        uph.user_id = ?
        join (select product_id,
              MAX(creation_date) AS max_creation_date
              from user_product_history
              where user_id = ?
              group by product_id) dt
        on dt.product_id = uph.product_id and
        dt.max_creation_date = uph.creation_date
        order by uph.creation_date desc';

        $result = $this->db->query($sql, array($data['user_id']));
        $records = array();
        foreach( $result->result_array() as $r ) {
            $r['product_id'] = (int) $r['product_id'];
            $r['sub_category_id'] = (int) $r['sub_category_id'];
            $r['merchant_id'] = (int) $r['merchant_id'];
            if (!isset($r['price_discount'])) $r['price_discount'] = '';
            $records[] = $r;
        }
        return $records;
    }