SQL | LeetCode 1327. 특정 월 기준 주문량 분석하기

Table: Products

+------------------+---------+
| Column Name      | Type    |
+------------------+---------+
| product_id       | int     |
| product_name     | varchar |
| product_category | varchar |
+------------------+---------+
product_id is the primary key (column with unique values) for this table.
This table contains data about the company's products.

 

Table: Orders

+---------------+---------+
| Column Name   | Type    |
+---------------+---------+
| product_id    | int     |
| order_date    | date    |
| unit          | int     |
+---------------+---------+
This table may have duplicate rows.
product_id is a foreign key (reference column) to the Products table.
unit is the number of products ordered in order_date.

 

Write a solution to get the names of products that have at least 100 units ordered in February 2020 and their amount.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
Products table:
+-------------+-----------------------+------------------+
| product_id  | product_name          | product_category |
+-------------+-----------------------+------------------+
| 1           | Leetcode Solutions    | Book             |
| 2           | Jewels of Stringology | Book             |
| 3           | HP                    | Laptop           |
| 4           | Lenovo                | Laptop           |
| 5           | Leetcode Kit          | T-shirt          |
+-------------+-----------------------+------------------+
Orders table:
+--------------+--------------+----------+
| product_id   | order_date   | unit     |
+--------------+--------------+----------+
| 1            | 2020-02-05   | 60       |
| 1            | 2020-02-10   | 70       |
| 2            | 2020-01-18   | 30       |
| 2            | 2020-02-11   | 80       |
| 3            | 2020-02-17   | 2        |
| 3            | 2020-02-24   | 3        |
| 4            | 2020-03-01   | 20       |
| 4            | 2020-03-04   | 30       |
| 4            | 2020-03-04   | 60       |
| 5            | 2020-02-25   | 50       |
| 5            | 2020-02-27   | 50       |
| 5            | 2020-03-01   | 50       |
+--------------+--------------+----------+
Output: 
+--------------------+---------+
| product_name       | unit    |
+--------------------+---------+
| Leetcode Solutions | 130     |
| Leetcode Kit       | 100     |
+--------------------+---------+
Explanation: 
Products with product_id = 1 is ordered in February a total of (60 + 70) = 130.
Products with product_id = 2 is ordered in February a total of 80.
Products with product_id = 3 is ordered in February a total of (2 + 3) = 5.
Products with product_id = 4 was not ordered in February 2020.
Products with product_id = 5 is ordered in February a total of (50 + 50) = 100.

1. Orders 테이블에서 2020-02-01 ~ 2020-02-29 사이 주문만 필터링.
2. 제품별로 총 주문량을 집계 (GROUP BY).
3. 100개 이상 주문된 제품만 필터링.
4. Products 테이블과 조인하여 product_name을 가져온다.

select p.product_name, sum(o.unit) as unit from (
    select * from orders where order_date like "2020-02-%" 
) o
join products p on p.product_id = o.product_id
group by o.product_id having sum(o.unit) >= 100

SELECT p.product_name, SUM(o.unit) AS unit
FROM Orders o
JOIN Products p ON o.product_id = p.product_id
WHERE o.order_date BETWEEN '2020-02-01' AND '2020-02-29'
GROUP BY p.product_id, p.product_name
HAVING SUM(o.unit) >= 100;