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- 销售表 Sales:
-
- +-------------+-------+
- | Column Name | Type |
- +-------------+-------+
- | sale_id | int |
- | product_id | int |
- | year | int |
- | quantity | int |
- | price | int |
- +-------------+-------+
- (sale_id, year) 是销售表 Sales 的主键.
- product_id 是关联到产品表 Product 的外键.
- 注意: price 表示每单位价格
- 产品表 Product:
-
- +--------------+---------+
- | Column Name | Type |
- +--------------+---------+
- | product_id | int |
- | product_name | varchar |
- +--------------+---------+
- product_id 是表的主键.
-
-
- 写一条SQL 查询语句获取 Sales 表中所有产品对应的 产品名称 product_name 以及该产品的所有 售卖年份 year 和 价格 price 。
-
-
-
- 示例:
-
- Sales 表:
- +---------+------------+------+----------+-------+
- | sale_id | product_id | year | quantity | price |
- +---------+------------+------+----------+-------+
- | 1 | 100 | 2008 | 10 | 5000 |
- | 2 | 100 | 2009 | 12 | 5000 |
- | 7 | 200 | 2011 | 15 | 9000 |
- +---------+------------+------+----------+-------+
-
- Product 表:
- +------------+--------------+
- | product_id | product_name |
- +------------+--------------+
- | 100 | Nokia |
- | 200 | Apple |
- | 300 | Samsung |
- +------------+--------------+
-
- Result 表:
- +--------------+-------+-------+
- | product_name | year | price |
- +--------------+-------+-------+
- | Nokia | 2008 | 5000 |
- | Nokia | 2009 | 5000 |
- | Apple | 2011 | 9000 |
- +--------------+-------+-------+
-
- 答案:
- select p.product_name, s.year, s.price
- from sales s
- left join product p on s.product_id = p.product_id

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