[Leetcode 1084] Sales Analysis III

原题说明

Table: Product

+————–+———+
| Column Name  | Type    |
+————–+———+
| product_id   | int     |
| product_name | varchar |
| unit_price   | int     |
+————–+———+
product_id is the primary key of this table.

Table: Sales

+————-+———+
| Column Name | Type    |
+————-+———+
| seller_id   | int     |
| product_id  | int     |
| buyer_id    | int     |
| sale_date   | date    |
| quantity    | int     |
| price       | int     |
+—— ——+———+
This table has no primary key, it can have repeated rows.
product_id is a foreign key to Product table.

 

Write an SQL query that reports the products that were only sold in spring 2019. That is, between 2019-01-01 and 2019-03-31 inclusive.

The query result format is in the following example:

Product table:
+————+————–+————+
| product_id | product_name | unit_price |
+————+————–+————+
| 1          | S8           | 1000       |
| 2          | G4           | 800        |
| 3          | iPhone       | 1400       |
+————+————–+————+

Sales table:
+———–+————+———-+————+———-+——-+
| seller_id | product_id | buyer_id | sale_date  | quantity | price |
+———–+————+———-+————+———-+——-+
| 1         | 1          | 1        | 2019-01-21 | 2        | 2000  |
| 1         | 2          | 2        | 2019-02-17 | 1        | 800   |
| 2         | 2          | 3        | 2019-06-02 | 1        | 800   |
| 3         | 3          | 4        | 2019-05-13 | 2        | 2800  |
+———–+————+———-+————+———-+——-+
Result table:
+————-+————–+
| product_id  | product_name |
+————-+————–+
| 1           | S8           |
+————-+————–+
The product with id 1 was only sold in spring 2019 while the other two were sold after.

解题思路

题目要求找出只在2019年销售的product。

对salse表中的product_id进行group by操作，并与product表的product_id进行join就可以了。

示例代码 (mysql)

SELECT s.product_id, p.product_name
FROM Sales as s
JOIN Product as p
ON s.product_id = p.product_id
GROUP BY s.product_id
HAVING MIN(s.sale_date) >= '2019-01-01' AND
       MAX(s.sale_date) <= '2019-03-31'

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