SQL Server 按每小时日期时间计数进行分组？

Question

    create table #Events
(
    EventID int identity primary key,
    StartDate datetime not null,
    EndDate datetime not null
)
go
insert into #Events (StartDate, EndDate)
select '2007-01-01 12:44:12 AM', '2007-01-01 12:45:34 AM' union all
select '2007-01-01 12:45:12 AM', '2007-01-01 12:46:34 AM' union all
select '2007-01-01 12:46:12 AM', '2007-01-01 12:47:34 AM' union all
select '2007-01-02 5:01:08 AM', '2007-01-02 5:05:37 AM' union all
select '2007-01-02 5:50:08 AM', '2007-01-02 5:55:59 AM' union all
select '2007-01-03 4:34:12 AM', '2007-01-03 4:55:18 AM' union all
select '2007-01-07 3:12:23 AM', '2007-01-07 3:52:25 AM'

（向 http://www 致歉.sqlteam.com/article/working-with-time-spans-and-durations-in-sql-server 用于收获他们的基本sql）

我试图找到一小时内发生的事件的计数，所以结果集看起来像这个：

2007-01-01      12:00     3
2007-01-02       5:00     2
2007-01-03       4:00     1
2007-01-07       3:00     1

我一直在玩 dateadd 和 round 和 grouping，但没有得到它。有人可以帮忙吗？

谢谢。

Answer 1

这个怎么样？假设 SQL Server 2008：

SELECT CAST(StartDate as date) AS ForDate,
       DATEPART(hour,StartDate) AS OnHour,
       COUNT(*) AS Totals
FROM #Events
GROUP BY CAST(StartDate as date),
       DATEPART(hour,StartDate)

对于 2008 之前版本：

SELECT DATEADD(day,datediff(day,0,StartDate),0)   AS ForDate,
       DATEPART(hour,StartDate) AS OnHour,
       COUNT(*) AS Totals
FROM #Events
GROUP BY CAST(StartDate as date),
       DATEPART(hour,StartDate)

这会导致：

ForDate                 | OnHour | Totals
-----------------------------------------
2011-08-09 00:00:00.000     12       3

Answer 2

或者，只需按小时和日期进行分组：

SELECT  CAST(Startdate as DATE) as 'StartDate', 
        CAST(DATEPART(Hour, StartDate) as varchar) + ':00' as 'Hour', 
        COUNT(*) as 'Ct'
FROM #Events
GROUP BY CAST(Startdate as DATE), DATEPART(Hour, StartDate)
ORDER BY CAST(Startdate as DATE) ASC

输出：

StartDate   Hour    Ct
2007-01-01  0:00    3
2007-01-02  5:00    2
2007-01-03  4:00    1
2007-01-07  3:00    1

Answer 3

我在其他地方找到了这个。我喜欢这个答案！

SELECT [Hourly], COUNT(*) as [Count]
  FROM 
 ( SELECT 
     dateadd(hh, datediff(hh, '20010101', [date_created]), '20010101') as [Hourly]
   FROM table) idat
 GROUP BY [Hourly]

Answer 4

您还可以通过使用以下 SQL 将日期和时间放在同一列中并使用正确的日期时间格式并按日期时间排序来实现此目的

SELECT  dateadd(hour, datediff(hour, 0, StartDate), 0) as 'ForDate', 
    COUNT(*) as 'Count' 
FROM #Events
GROUP BY dateadd(hour, datediff(hour, 0, LogTime), 0)
ORDER BY ForDate