mysql - SQL - 报告中的多个分组

Question

我有一个与此结构类似的表格:

ID
Incident_Name
Category
Source

我需要一份报告来显示按类别分组的所有事件，然后显示该类别中具有特定源值的事件数量。

Category   | Amount | Percentage of Total | Source_1 | Source_2 | Source 3
----------------------------------------------------------------------------
Category 1 | 5      | 25%                 | 1        | 3        | 2
Category 2 | 15     | 75%                 | 10       | 2        | 3

我正在使用 MySQL - 我将如何做到这一点。

分组并获取数量/百分比很好，但不确定我将如何做剩下的事情。

SELECT Category, COUNT(*) AS Amount, (COUNT(*) / (SELECT COUNT(*) FROM MyTable)) * 100 AS 'Percentage of Total', 
FROM MyTable
GROUP BY Category;

任何建议

Answer 1

我认为这就是您正在尝试做的事情。

SELECT Category, 
COUNT(*) AS Amount,
(COUNT(*) / (SELECT COUNT(*) FROM MyTable)) * 100 AS 'Percentage of Total', 
SUM(source=someval1) as Source_1, --this may need a change
SUM(source=someval2) as Source_2, --this may need a change
SUM(source=someval3) as Source_3  --this may need a change
FROM MyTable
GROUP BY Category;