sql-server - 如何在 ms-sql 中根据日期和小时对数据进行分组？

Question

我的表 activity_count 中有以下数据

Activitydate        |count
2013-12-20:18:25:45  10
2013-12-20:18:23:40  20
2013-12-20:17:25:45   5
2013-12-20:17:25:45  10
2013-12-20:17:25:45  10

我想得到每个小时的总计数，即结果应该如下

Activitydate        |count
2013-12-20:18:00:00   30
2013-12-20:17:00:00   25

Answer 1

如果您正在使用mySQL以下尝试：

SELECT CONCAT(LEFT(DATE(activitydate),10),' ',HOUR(activitydate),':00:00') as DateHour,
SUM(count) as TotalCount
FROM activity_count
GROUP BY DATE(activitydate),HOUR(activitydate)

见我的演示。

但是，如果MSSQL尝试这个：

SELECT CAST(CAST(activitydate as DATE) AS nvarchar(15))+' '+CAST(datepart(HOUR,activitydate) as CHAR(2))+':00:00' as DateHour,
SUM([count]) as TotalCount
FROM activity_count
GROUP BY CAST(CAST(activitydate as DATE) AS nvarchar(15)),DATEPART(HOUR, activitydate)

参见 MSSQL演示

Answer 2

请试试这个

  select cast(cast(Activitydate as date) as datetime)+cast(datepart(hour,Activitydate),
  count(*)
   from activity_count 
  group by cast(cast(Activitydate as date) as datetime)+cast(datepart(hour,Activitydate)

Answer 3

试用HOUR功能

 select 
Activitydate,        
count(*) as 'count'
from activity_count
GROUP BY HOUR(Activitydate)

Answer 4

小时（时间）

 HOUR(time)

返回时间的小时。对于时间值，返回值的范围是 0 到 23。但是，TIME 值的范围实际上要大得多，因此 HOUR 可以返回大于 23 的值。