8/20 MYSQL(找出只在2019-01-01到2019-03-31期間販售的產品)

Table: Product

+--------------+---------+
| Column Name  | Type    |
+--------------+---------+
| product_id   | int     |
| product_name | varchar |
| unit_price   | int     |
+--------------+---------+
product_id is the primary key (column with unique values) of this table.
Each row of this table indicates the name and the price of each product.

Table: Sales

+-------------+---------+
| Column Name | Type    |
+-------------+---------+
| seller_id   | int     |
| product_id  | int     |
| buyer_id    | int     |
| sale_date   | date    |
| quantity    | int     |
| price       | int     |
+-------------+---------+
This table can have duplicate rows.
product_id is a foreign key (reference column) to the Product table.
Each row of this table contains some information about one sale.

 

Write a solution to report the products that were only sold in the first quarter of 2019. That is, between 2019-01-01 and 2019-03-31 inclusive.

Return the result table in any order.

The result format is in the following example.

 

Example 1:

Input: 
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  |
+-----------+------------+----------+------------+----------+-------+
Output: 
+-------------+--------------+
| product_id  | product_name |
+-------------+--------------+
| 1           | S8           |
+-------------+--------------+
Explanation: 
The product with id 1 was only sold in the spring of 2019.
The product with id 2 was sold in the spring of 2019 but was also sold after the spring of 2019.
The product with id 3 was sold after spring 2019.
We return only product 1 as it is the product that was only sold in the spring of 2019.

# Write your MySQL query statement below

select p.product_id ,p.product_name FROM Product AS p

#選擇要輸出的欄位

join Sales AS s on p.product_id =s.product_id

#將兩個Product 和 Sales 表合併

GROUP BY s.product_id  

#用產品名稱進行分組

HAVING MAX(s.sale_date)  between '2019-01-01' AND '2019-03-31'

#限定產品賣出的最後日期在特定時間內

AND MIN(s.sale_date) between '2019-01-01' AND '2019-03-31'

#限定產品受次賣出的日期在特定時間內

-----------------參考答案

# Write your MySQL query statement below
select Product.product_id, Product.product_name  
from Product join Sales 
on Product.product_id = Sales.product_id 
group by Sales.product_id 
having min(Sales.sale_date) >= '2019-01-01' and max(Sales.sale_date) <= '2019-03-31';

!!!!!!!!!這邊在判斷產品最後賣出以及最初賣出的日期必須分開判斷

-----------------參考答案

select product_id,product_name from Product
where product_id not in (select distinct product_id
from Sales
where sale_date<'2019-01-01' or sale_date>'2019-03-31') 
and product_id in (select distinct product_id from
Sales)

-----------------參考答案

# SELECT product_id, product_name
# FROM Product
# WHERE product_id in
# (
#   SELECT product_id
#   FROM Sales
#   WHERE (sale_date >= DATE('2019-01-01')) AND (sale_date <= DATE('2019-03-31'))
#   EXCEPT
#   SELECT product_id
#   FROM Sales
#   WHERE (sale_date < DATE('2019-01-01')) OR (sale_date > DATE('2019-03-31'))
# )

SELECT product_id, product_name
FROM Product 
WHERE product_id in
  (
  SELECT t1.product_id
  FROM
    (
      SELECT Sales.product_id
      FROM Sales
      WHERE (sale_date >= DATE('2019-01-01')) AND (sale_date <= DATE('2019-03-31'))
    ) AS t1
    LEFT JOIN
    (
      SELECT Sales.product_id
      FROM Sales
      WHERE (sale_date < DATE('2019-01-01')) OR (sale_date > DATE('2019-03-31'))
    ) AS t2
    ON t1.product_id = t2.product_id
  # JOIN as t3
  # ON t1.product_id = t3.product_id
  WHERE t2.product_id is NULL
  )