SQL Sum（） - 0在字段中排除聚集中的行嗎？

Question

考慮以下查詢：

$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的兩種用途（）正試圖聚集訂單總額和已被退還的總量。他們是正確出來的時候，當quant_refunded字段不爲0 ...例如利用這個數據（不包括主鍵，ITEM_ID爲了簡單起見，假設每行是一個獨特的項目）：

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

在這種情況下「訂單1」的兩個集合是不同的，並按預期行事。但對於「訂單2」這兩個數字是相同的 - 兩個數字都是我期待的refund_total。看來quant_refunded中帶有「0」的行將被排除在order_total聚合之外。

希望對此有足夠的解釋。請讓我知道你是否需要更多的信息，我會修改。謝謝！

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"; 

將其改爲HAVING子句。如果任何quant_refunded行大於0，HAVING MAX將保留它。