mysql - SQL Sum() - 字段中的 0 从聚合中排除行？

Question

考虑以下查询:

$query = "
SELECT a_orders.id, a_orders.billing,
   SUM(a_order_rows.quant_refunded*a_order_rows.price*((100-a_orders.discount)*.01)) as refund_total,
   SUM(a_order_rows.quant*a_order_rows.price*((100-a_orders.discount)*.01)) as order_total 
FROM a_order_rows JOIN a_orders 
ON a_order_rows.order_id = a_orders.id 
WHERE a_order_rows.quant_refunded > 0 
GROUP BY a_orders.id, a_orders.billing 
ORDER BY a_orders.id DESC 
LIMIT 50";

SUM() 的两个用途是尝试汇总订单总额和已退款总额。当 quant_refunded 字段不为 0 时，它们会正确显示...例如，采用此数据(为了简单起见，不包括主键、item_id，假设每一行都是唯一的项目):

Table: a_order_rows
Fields: order_id, quant, quant_refunded
1, 1, 1
1, 2, 1
2, 1, 1
2, 1, 0

在“阶数 1”的情况下，两个聚合不同并且行为符合预期。但对于“订单 2”，这两个数字是相同的 - 这两个数字都是我期望的 returned_total 的值。 Quant_refunded 中带有“0”的行似乎已从 order_total 聚合中排除。

希望这能得到足够彻底的解释。如果您需要更多信息，请告诉我，我会修改。谢谢!

Answer 1

$query = "
SELECT a_orders.id, a_orders.billing,
   SUM(a_order_rows.quant_refunded*a_order_rows.price*((100-a_orders.discount)*.01)) as refund_total,
   SUM(a_order_rows.quant*a_order_rows.price*((100-a_orders.discount)*.01)) as order_total 
FROM a_order_rows JOIN a_orders 
  ON a_order_rows.order_id = a_orders.id 
GROUP BY a_orders.id, a_orders.billing 
HAVING MAX(a_order_rows.quant_refunded) > 0 
ORDER BY a_orders.id DESC 
LIMIT 50";

将其更改为 HAVING 子句。如果任何 quant_refunded 行 > 0，HAVING MAX 将保留它。