按组BY求和的多列

Question

我的数据库中有这些数据

Purchase ID: 0012 <br>
Product: 1 <br>
Delivered: 100

Pruchase ID: 0013<br>
Product: 1<br>
Delivered: 10

当我对相同产品求和时，应该为110，但是当我使用此查询时，总和将为440

SELECT `purchase_orders`.`product`, SUM(purchase_orders.delivered) as system_count, `products`.`code`
FROM `purchase_orders`
JOIN `products` ON `products`.`id` = `purchase_orders`.`product`
WHERE `purchase_orders`.`delivery_status` = 4
GROUP BY `purchase_orders`.`product`

任何人都可以帮助我解决我的SQl问题吗？

Answer 1

您也应该GROUP BY products.code。

如下所示

SELECT `purchase_orders`.`product`, SUM(purchase_orders.delivered) as system_count, `products`.`code`
FROM `purchase_orders`
JOIN `products` ON `products`.`id` = `purchase_orders`.`product`
WHERE `purchase_orders`.`delivery_status` = 4
GROUP BY `purchase_orders`.`product`, `products`.`code`