計算給定日期過去7天內的用戶數

Question

我有表格，我必須更新該特定日期的用戶數量以及過去7天內從指定日期起的用戶數量。樣本數據看起來像

Date UserCountToday UserCount7days 
20120911 907575 
20120910 953629 
20120909 1366180 
20120908 1388916 
20120907 1009425 
20120906 918638 
20120905 956770 
20120904 1018152 
20120903 1306341 

Answer 1

嘗試：

with cte as 
     (select *,ROW_NUMBER() over(order by [Date]) as row_num 
     from t_users) 
select [Date],UserCountToday, (select SUM(UserCountToday) 
from cte c1 where c.row_num>=c1.row_num 
and abs(c.row_num-c1.row_num)<7) as UserCount7days 
from cte c 

結果

Date UserCountToday UserCount7days 
20120903 1306341 1306341 
20120904 1018152 2324493 
20120905 956770 3281263 
20120906 918638 4199901 
20120907 1009425 5209326 
20120908 1388916 6598242 
20120909 1366180 7964422 
20120910 953629 7611710 
20120911 907575 7501133 

Answer 2

;WITH CTE as (select row_number() over (order by date) as rn,Date,UserCountToday,UserCount7days from tbl5) 

,CTERec as (
select rn,Date,UserCountToday ,UserCountToday as UserCount7days from CTE where rn=1 
union all 
select c.rn,c.Date,c.UserCountToday ,c.UserCountToday+c1.UserCount7days as UserCount7days from CTERec c1 inner join CTE c 
on c.rn=c1.rn+1 
) 

select Date,UserCountToday,CASE WHEN rn<=7 then UserCount7days else (UserCount7days-(select UserCount7days from CTERec where rn=c.rn-7)) end asUserCount7days from CTERec c