MEDIUM

Author: evanmathew

1070. Product Sales Analysis III.sql

@@ -1,3 +1,75 @@
+-- Problem:
+
+/*
+Table: Sales
+
++-------------+-------+
+| Column Name | Type  |
++-------------+-------+
+| sale_id     | int   |
+| product_id  | int   |
+| year        | int   |
+| quantity    | int   |
+| price       | int   |
++-------------+-------+
+(sale_id, year) is the primary key (combination of columns with unique values) of this table.
+product_id is a foreign key (reference column) to Product table.
+Each row of this table shows a sale on the product product_id in a certain year.
+Note that the price is per unit.
+ 
+
+Table: Product
+
++--------------+---------+
+| Column Name  | Type    |
++--------------+---------+
+| product_id   | int     |
+| product_name | varchar |
++--------------+---------+
+product_id is the primary key (column with unique values) of this table.
+Each row of this table indicates the product name of each product.
+ 
+
+Write a solution to select the product id, year, quantity, and price for the first year of every product sold.
+
+Return the resulting table in any order.
+
+The result format is in the following example.
+
+ 
+
+Example 1:
+
+Input: 
+Sales table:
++---------+------------+------+----------+-------+
+| sale_id | product_id | year | quantity | price |
++---------+------------+------+----------+-------+ 
+| 1       | 100        | 2008 | 10       | 5000  |
+| 2       | 100        | 2009 | 12       | 5000  |
+| 7       | 200        | 2011 | 15       | 9000  |
++---------+------------+------+----------+-------+
+Product table:
++------------+--------------+
+| product_id | product_name |
++------------+--------------+
+| 100        | Nokia        |
+| 200        | Apple        |
+| 300        | Samsung      |
++------------+--------------+
+Output: 
++------------+------------+----------+-------+
+| product_id | first_year | quantity | price |
++------------+------------+----------+-------+ 
+| 100        | 2008       | 10       | 5000  |
+| 200        | 2011       | 15       | 9000  |
++------------+------------+----------+-------+
+*/
+
+-------------------------------------------------------------------------------
+
+-- Solution:
+
 SELECT product_id,year AS first_year,quantity,price
 FROM Sales
 WHERE (product_id, year) IN