Question

我有一个包含4个字段的MySQL表。它将用户存储多少次称为模块/动作组合。该表具有Composite Promary Key（CPK），由模块 - 动作 - 用户三元组组成。

analyze_cumulated 
----------------- 
module (CPK) VARCHAR,
action (CPK) VARCHAR, 
user (CPK) INT, 
times_called INT

我想编写一个查询来获取每个模块/操作对调用的次数，以及总调用的百分比。我有这个查询工作正常但我想知道在主查询的SELECT部分中没有SELECT子查询是否还有其他方法可以做同样的事情。

SELECT 
    module, 
    SUM(times_called),
    SUM(times_called)*100/(SELECT SUM(times_called) FROM analyze_cumulated)
FROM analyze_cumulated
GROUP BY module

Answer 1

你可以加入它：

SELECT 
    module, 
    SUM(times_called),
    SUM(times_called)*100/t.tot
FROM analyze_cumulated
JOIN (SELECT SUM(times_called) tot FROM analyze_cumulated) t
GROUP BY module;

第二个选项是使用临时变量：

SELECT SUM(times_called) into @tot FROM analyze_cumulated;
SELECT 
    module, 
    SUM(times_called),
    SUM(times_called)*100/@tot
FROM analyze_cumulated
GROUP BY module;

Answer 2

SELECT 
    module, 
    SUM(times_called) as Times_Called,
    max((times_called/SUM(times_called))*100) as Percentage
FROM analyze_cumulated
GROUP BY module

如何在MySQL查询中得到数字行的总和，我也有GROUP BY

2 个答案: