每天平均完成的事件（月）

Question

使用 SQL，我如何计算每月平均每天完成的事件数？

样本数据：

ID  Fullname    Events  Status  DateContacted   UserID
1   Jack    Phone Call  Completed   2017-03-10 00:00:00.000 14587bg   
2   Dawn    Meeting Completed   2017-03-08 00:00:00.000 15879uj   
3   Helen   Phone Call  NULL    2017-02-02 00:00:00.000 89751po   
4   Sam Appointment Completed   2017-02-10 00:00:00.000 35784ly   
5   David   Skype   Completed   2017-01-01 00:00:00.000 3337jy    
6   Jack    Skype   Completed   2017-01-14 00:00:00.000 14587bg 

谢谢

Answer 1

计算完成的事件数并计算该月的天数。让我假设你不关心没有事件的日子。

select year(datecontacted) as yyyy, month(datecontacted) as mm,
       (sum(case when status = 'Completed' then 1.0 else 0 end) / 
        count(distinct cast(datecontact as date))
       ) as avg_completed_per_day
from sample s
group by year(datecontacted), month(datecontacted)
order by yyyy, mm;