如何在MySQL中使用Group BY的SUM函数？

Question

我有一个 SQL 声明 returns 一些记录取决于一些给定的变量。

查询：

SELECT
     country
    ,(MAX(d_views) - MIN(d_views)) AS viewz 
FROM mv_data
WHERE add_date BETWEEN '2022-01-22' AND '2022-01-22' 
GROUP BY title
ORDER BY viewz DESC;

输出：

country	viewz
NG	14735
NG	12494
GH	6099
GH	5181
GH	3381
NG	3293
GH	2288
NG	169

我要找的是： 要使用 SUM() 函数根据国家/地区汇总所有 viewz，例如：

country	viewz
NG	30691
GH	16949

这就是我所做的：

SELECT
     country
    ,SUM(MAX(d_views) - MIN(d_views)) AS viewz 
FROM mv_data
WHERE add_date BETWEEN '2022-01-26' AND '2022-01-26'
GROUP BY title
ORDER BY viewz DESC;

但是我收到这个错误：

#1111 - Invalid use of group function

我也试过 GROUP BY country 没有 SUM() 函数，结果不正确：

查询：

SELECT
     country
    ,(MAX(d_views) - MIN(d_views)) AS viewz 
FROM mv_data
WHERE add_date BETWEEN '2022-01-26' AND '2022-01-26'
GROUP BY country
ORDER BY viewz DESC;

输出：

country	viewz
NG	4918377
GH	8185474

我做错了什么？

注意：d_views 是我的 table 中的一个字段。根据给定的日期，我们有一个最小值和一个最大值。

Answer 1

使用第一个作为第二个的子查询

SELECT
   country
   SUM(viewz) as viewz
FROM (SELECT
     country
    ,MAX(d_views) - MIN(d_views) AS viewz 
FROM mv_data
WHERE add_date BETWEEN '2022-01-26' AND '2022-01-26'
GROUP BY title) t1
GROUP BY country
ORDER BY viewz DESC;

Answer 2

如果您想使用 SUM() 函数 sum-up 根据他们所在国家/地区的所有视图，只需使用以下命令；

SELECT
     country
    ,SUM(d_view) AS viewz 
FROM mv_data
WHERE add_date BETWEEN '2022-01-26' AND '2022-01-26'
GROUP BY country
ORDER BY viewz DESC;

如何在MySQL中使用Group BY的SUM函数？

How to use the SUM function with Group BY in MySQL?

mysql

sql

group-by