SQL返回日期范围,即使count为null

Question

我在计算UsersID过去7天内的登录总数().我会计算此日期范围内的用户ID总数以及按日期分组.我的问题是,如果没有为日期记录用户ID,则不显示日期.

所以我需要在没有登录的日期显示0.

我的代码是:

SET @StartDate = CONVERT(varchar(10),DATEADD(day,-7, GETDATE()), 101) +  ' 00:00.00';
SET @EndDate = DATEADD(day,7, @StartDate);

SELECT CONVERT(DATE, [DateTime]) as LoginDate, COUNT(UsersID) AS TotalForDay
FROM [STATS].[dbo].[UsersLogin]
WHERE [DateTime]>@StartDate 
AND [DateTime]<@EndDate
GROUP BY CONVERT(DATE, [DateTime])
ORDER BY LoginDate desc;

Answer 1

您需要一个包含日期值的单独表,请尝试此操作

DECLARE @startdate datetime, @enddate datetime
SET @StartDate = CONVERT(varchar(10),DATEADD(day,-7, GETDATE()), 101) +  ' 00:00.00';
SET @EndDate = DATEADD(day,7, @StartDate);
;with cte as
(
    select @startdate DateValue
    union all
    select DateValue + 1
    from    cte   
    where   DateValue + 1 < @enddate
)


select a.DateValue as LoginDate,  COUNT(UsersID) AS TotalForDay
from cte a
LEFT outer join [STATS].[dbo].[UsersLogin] b 
on CONVERT(varchar(15), a.DateValue,101) = CONVERT(varchar(15), b.[DateTime],101)
group by a.DateValue
order by a.DateValue desc

按小时分组:

DECLARE @startdate datetime, @enddate datetime
SET @StartDate = CONVERT(varchar(10),DATEADD(day,-7, GETDATE()), 101) +  ' 00:00.00';
SET @EndDate = DATEADD(day,7, @StartDate);
;with cte as
(
    select @startdate DateValue
    union all
    select DATEADD (hh,1,DateValue)
    from    cte   
    where   DATEADD (hh,1,DateValue) < @enddate
)


select a.DateValue as LoginDate,  COUNT(UsersID) AS TotalForDay
from cte a
LEFT outer join [STATS].[dbo].[UsersLogin] b 
on CONVERT(varchar(15), a.DateValue,101) = CONVERT(varchar(15), b.[DateTime],101)
group by a.DateValue
order by a.DateValue desc
OPTION (MAXRECURSION 0)