按Processname分组的标准偏差日期时间列(Standard Deviation over Datetime column grouped by Processname)

按Processname分组的标准偏差日期时间列(Standard Deviation over Datetime column grouped by Processname)

我有一个表包含字段ProcessName ， StartDate和EndDate 。 我需要知道EndDate的标准偏差，以便知道我可以等待进程完成的时间限制。 根据此标准偏差，如果某个流程需要花费太多时间来运行，则会发送电子邮件。

我的想法是使用以下查询：

select ProcessName, STDEV(tm) from ( select ProcessName, cast(EndDate as decimal(18,6)) tm from Reports..ExecutionControl ) t1 group by ProcessName

但是，首先我不知道它返回什么（如果它是百分比），也许这是缺乏统计理解，我也需要获得一个过程可以采取的时间限制，并且它不计算它。

有人可以帮我解决这个问题吗？ 在此先感谢所有人！

I have a Table with fields ProcessName, StartDate and EndDate. I need to know the standard deviation of the EndDate in order to know the limit of time I can wait for a process to finish. Based on this standard deviation e-mails will be sent if some process is taking too much time to run.

My idea was to use the following query:

select ProcessName, STDEV(tm) from ( select ProcessName, cast(EndDate as decimal(18,6)) tm from Reports..ExecutionControl ) t1 group by ProcessName

But, first I don't know what it returns (if it is percentage or not), and maybe this is a lack of statistical understanding, and also I need to get the time limit a process can take, and it is not calculating it.

Could someone help me to sort this out? Thanks in advance to all!

最满意答案

嗯，我不确定你如何在没有平均值的情况下使用标准偏差，但那是你的问题。

我希望这样的查询：

select ProcessName, STDEV(dateadiff(second, Startdate, Enddate)) as stdev_dur from Reports..ExecutionControl group by ProcessName;

也就是说，标准偏差是根据持续时间而非EndDate计算的。

Hmmm, I'm not sure how you would use the standard deviation without an average, but that is your question.

I would expect a query like this:

select ProcessName, STDEV(dateadiff(second, Startdate, Enddate)) as stdev_dur from Reports..ExecutionControl group by ProcessName;

That is, the standard deviation is calculated based on the duration, not EndDate.