1571. 仓库经理

表: Products

+---------------+---------+
| Column Name | Type |
+---------------+---------+
| product_id | int |
| product_name | varchar |
| Width | int |
| Length | int |
| Height | int |
+---------------+---------+
product_id 是该表主键.
该表的行包含了每件商品以英尺为单位的尺寸(宽度, 长度和高度)信息.
 

写一个 SQL 查询来报告, 每个仓库的存货量是多少立方英尺.

仓库名
存货量
返回结果没有顺序要求.

查询结果如下例所示.

Warehouse 表:
+------------+--------------+-------------+
| name | product_id | units |
+------------+--------------+-------------+
| LCHouse1 | 1 | 1 |
| LCHouse1 | 2 | 10 |
| LCHouse1 | 3 | 5 |
| LCHouse2 | 1 | 2 |
| LCHouse2 | 2 | 2 |
| LCHouse3 | 4 | 1 |
+------------+--------------+-------------+

Products 表:
+------------+--------------+------------+----------+-----------+
| product_id | product_name | Width | Length | Height |
+------------+--------------+------------+----------+-----------+
| 1 | LC-TV | 5 | 50 | 40 |
| 2 | LC-KeyChain | 5 | 5 | 5 |
| 3 | LC-Phone | 2 | 10 | 10 |
| 4 | LC-T-Shirt | 4 | 10 | 20 |
+------------+--------------+------------+----------+-----------+

Result 表:
+----------------+------------+
| warehouse_name | volume |
+----------------+------------+
| LCHouse1 | 12250 |
| LCHouse2 | 20250 |
| LCHouse3 | 800 |
+----------------+------------+

解题方案：

select `name` as warehouse_name, sum(voc) as volume from (SELECT `name`, units*Width*`Length`*`Height` as voc 

from Warehouse a

left join Products b

using(product_id)) as c

group by `name`