包含连接的子查询的MySQL总和

Question

我有一个包含表格中库存的表格

ID |Product ID | Movement |  Cumulative Quantity | Store ID
=================================================|=========
1  | 1         |  100     |  100                 |  1 
2  | 1         |  -4      |  96                  |  1
3  | 1         |  -1      |  95                  |  1
4  | 2         |  100     |  100                 |  1
5  | 1         |  100     |  100                 |  2

每一行基本上都有库存变动，最后一行 MAX(ID) 包含 cumulative_quantity，其中包含可用库存

另一个包含产品的表

ID | Product Name
====================
1  | Apple Juice
2  | Orange Juice

我正在寻找表单中的输出

Product ID | Product Name | Total Quantity at all stores
========================================================
1          | Apple Juice  | 195
2          | Orange Juice | 100

这是下表的简化版本

Store ID   | Product ID | Product Name | Cumulative Quantity
========================================================
1          | 1          | Apple Juice  | 95
1          | 2          | Orange Juice | 100
2          | 1          | Apple Juice  | 100
2          | 2          | Orange Juice | 0

Answer 1

这是一个相对简单的 SUM() 聚合，带有一个 JOIN。 SUM(Movement) 将得出所有商店可用的总数量。

SELECT
  inventories.productId,
  productName,
  SUM(Movement) AS `Total Quantity`
FROM inventories JOIN  products ON inventories.productId = products.productId
GROUP BY inventories.productId, productName