SQL同一个表，PHP分别查询2列数据的总和然后输出

//计算订单数量的总和

$query_num = "SELECT SUM(order_num) from hcf_order_db where order_id = XXX";
$arr_qn = mysqli_query($dbc,$query_num);
list($sum)=mysqli_fetch_row($arr_qn);

//计算订单金额的总和

$query_amount = "SELECT SUM(order_amount) from hcf_order_db where order_id = XXX";
$arr_qm = mysqli_query($dbc,$query_amount);
list($sum2)=mysqli_fetch_row($arr_qm);

然后就是PHP输出：

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