ecshop显示商品按月统计销售数量

$smarty->assign('goods_count', get_goods_coun($goods_id)); ，

/**
* 获取商品出售总数
*
* @access public
* @param integer $goods_id
* @return integer
*/
function get_goods_count($goods_id)
{
/* 统计时间段
$period = intval($GLOBALS['_CFG']['top10_time']);
if ($period == 1) // 一年
{
$ext = "AND o.add_time >'" . local_strtotime('-1 years') . "'";
}
elseif ($period == 2) // 半年
{
$ext = "AND o.add_time > '" . local_strtotime(‘-6 months’) . "'";
}
elseif ($period == 3) // 三个月
{
$ext = " AND o.add_time > '" . local_strtotime('-3 months’) . "'";
}
elseif ($period == 4) // 一个月
{
$ext = " AND o.add_time > '" . local_strtotime('-1 months') . "'";
}
else
{
$ext = '';
}*/
/* 查询该商品销量 */
$sql = 'SELECT IFNULL(SUM(g.goods_number), 0) ' .
'FROM ' . $GLOBALS['ecs']->table('order_info') . 'AS o, ' .
$GLOBALS['ecs']->table('order_goods') . 'AS g ' .
"WHERE o.order_id = g.order_id " .
"AND o.order_status = '" . OS_CONFIRMED . "'" .
"AND o.shipping_status " . db_create_in(array(SS_SHIPPED, SS_RECEIVED)) .
" AND o.pay_status " . db_create_in(array(PS_PAYED, PS_PAYING)) .
" AND g.goods_id = '$goods_id'";
$sales_count = $GLOBALS['db']->getOne($sql);
return $sales_count;
}