task: #1070

README.md

@@ -46,6 +46,7 @@ Have a good contributing!
 2. [Medium](./leetcode/medium/)
     - [176. Second Highest Salary](./leetcode/medium/176.%20Second%20Highest%20Salary.sql)
     - [184. Department Highest Salary](./leetcode/medium/184.%20Department%20Highest%20Salary.sql)
+    - [1070. Product Sales Analysis III](./leetcode/medium/1070.%20Product%20Sales%20Analysis%203.sql)
     - [1158. Market Analysis 1](./leetcode/medium/1158.%20Market%20Analysis%201.sql)
 
 ## License

leetcode/medium/1070. Product Sales Analysis 3.sql

@@ -0,0 +1,42 @@
+/*
+Question 1070. Product Sales Analysis 3
+Link: https://leetcode.com/problems/product-sales-analysis-iii/description/
+
+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 records a sale of a product in a given year.
+A product may have multiple sales entries in the same year.
+Note that the per-unit price.
+
+Write a solution to find all sales that occurred in the first year each product was sold.
+
+For each product_id, identify the earliest year it appears in the Sales table.
+
+Return all sales entries for that product in that year.
+
+Return a table with the following columns: product_id, first_year, quantity, and price.
+Return the result in any order.
+*/
+
+SELECT 
+    s1.product_id,
+    s1.year AS first_year,
+    s1.quantity,
+    s1.price
+FROM Sales AS s1
+WHERE s1.year = (
+    SELECT MIN(s2.year)
+    FROM Sales AS s2
+    WHERE s1.product_id = s2.product_id
+)