如何在Kusto中基于App分组计算各Code的请求占比？

你可以通过窗口函数或者分组关联的方式实现按App分组计算请求占比，以下是两种可行方案：

方案一：使用窗口函数（推荐，更简洁高效） #

datatable (Code:string, App:string, Requests:long)
[
 "200", "tra", 63,
 "200", "api", 1036,
 "302", "web", 12,
 "200", "web", 219,
 "500", "web", 2,
 "404", "api", 18
]
| extend AppTotalRequests = sum(Requests) over (partition by App)
| extend Percentage = round(100.0 * Requests / AppTotalRequests, 2)
| project Code, App, Requests, AppTotalRequests, Percentage

核心逻辑是用sum(Requests) over (partition by App)为每一行计算对应App的总请求数，再用当前行的请求数除以该分组总数，得到占比并保留两位小数。比如api分组的总请求数为1054，200状态的请求占比就是1036/1054*100≈98.29%，符合预期。

方案二：使用分组关联 #

如果更熟悉join语法，也可以先按App分组计算总数，再关联原表：

datatable (Code:string, App:string, Requests:long)
[
 "200", "tra", 63,
 "200", "api", 1036,
 "302", "web", 12,
 "200", "web", 219,
 "500", "web", 2,
 "404", "api", 18
]
| as T
| join kind=inner (
    T 
    | summarize AppTotalRequests = sum(Requests) by App
) on App
| extend Percentage = round(100.0 * Requests / AppTotalRequests, 2)
| project Code, App, Requests, AppTotalRequests, Percentage

内容的提问来源于stack exchange，提问作者LukeB