MySQL：查找总价既不是最高也不是最低的产品类别？

Posted 2023-02-16

【中文标题】MySQL：查找总价既不是最高也不是最低的产品类别？

【英文标题】：MySQL: Find categories of products whose total price is neither maximum nor minimum?

【发布时间】：2021-03-31 11:42:54

【问题描述】：

我的数据：

product Table:
Category_ID Product_ID Price
1           12         120
1           19         234
2           10         129
3           34         145
3           11         100
4           8          56

我想使用 mysql 查找总价既不是最高也不是最低的类别。

结果：

Category_ID Total_Price
2           129
3           245

我使用以下查询找到了这一点，但我想知道是否有任何有效且更好的查询。

SELECT P.Category_ID, SUM(P.Price) AS Total_Price 
FROM Product P
GROUP BY P.Category_ID
HAVING SUM(P.Price) 
NOT IN
(
(SELECT MAX(Total) FROM (SELECT SUM(Price) AS Total
FROM Product GROUP BY Category_ID) AS T1),

(SELECT MIN(Total) FROM (SELECT SUM(Price) AS Total
FROM Product GROUP BY Category_ID) AS T2)
)

谢谢。

【参考方案1】：

如果你运行的是 MySQL 8.0，你可以使用窗口函数将类别按价格升序和降序排列，然后进行过滤：

select *
from (
    select category_id, sum(price) as sum_price,
        rank() over(order by sum(price)) rn_asc,
        rank() over(order by sum(price) desc) rn_desc
    from product p
    group by category_id
) p
where rn_asc > 1 and rn_desc > 1

在早期版本中，一种替代方法使用子查询：

select category_id, sum(price) as sum_price
from product p
group by category_id
having sum(price) > (select sum(price) from product group by category_id order by sum(price) limit 1)
   and sum(price) < (select sum(price) from product group by category_id order by sum(price) desc limit 1)

此查询将使(category_id, price) 上的索引受益。