1070. 产品销售分析 III

产品销售分析 III"/>

1070. 产品销售分析 III

SQL架构

销售表 Sales：

+-------------+-------+
| Column Name | Type  |
+-------------+-------+
| sale_id     | int   |
| product_id  | int   |
| year        | int   |
| quantity    | int   |
| price       | int   |
+-------------+-------+
(sale_id, year) 是这张表的主键。
product_id 是产品表的外键。
这张表的每一行都表示：编号 product_id 的产品在某一年的销售额。
请注意，价格是按每单位计的。

产品表 Product：

+--------------+---------+
| Column Name  | Type    |
+--------------+---------+
| product_id   | int     |
| product_name | varchar |
+--------------+---------+
product_id 是这张表的主键。
这张表的每一行都标识：每个产品的 id 和 产品名称。

编写一个 SQL 查询，选出每个销售产品 第一年 销售的 产品 id、年份、数量 和 价格。

结果表中的条目可以按 任意顺序 排列。

查询结果格式如下例所示：

示例 1：

输入：
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      |
+------------+--------------+
输出：
+------------+------------+----------+-------+
| product_id | first_year | quantity | price |
+------------+------------+----------+-------+ 
| 100        | 2008       | 10       | 5000  |
| 200        | 2011       | 15       | 9000  |
+------------+------------+----------+-------+

select
s1.product_id,s1.first_year,s1.quantity,s1.price
from
(select
product_id, year first_year,quantity,price
from
Sales) s1
left join
(select
product_id,min(year) my
from
Sales
group by 
product_id) s2
on s1.product_id = s2.product_id where s1.first_year = s2.my

select
ss1.product_id,ss1.year first_year,ss1.quantity,ss1.price
from
(
select
*,dense_rank() over(partition by product_id order by year) dr
from
Sales
) ss1
where ss1.dr = 1

selectproduct_id, year first_year, quantity, price
from Sales
where (product_id,year) in ( select product_id,min(year) from sales group by product_id )

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