SQL Server：计算每小时的行数

Question

我有一个包含2628行的表。我想每小时计数一次。我有一个completion_time列，它告诉每条记录的日期时间。

Zeppelin

我只能找到一个小时的时间。

select count(*) 
from billing b 
where b.completion_time >= '2019-04-16 23:50:23' 
  and b.completion_time <='2019-04-17 00:50:22'

日期时间最多为9小时。即该过程始于2016-04-16 23:50:23，结束于2019-04-17 08:16:49。所以我想要每小时的总计数。

更新1

我想要类似下面的输出

如何实现？任何帮助将不胜感激。

Answer 1

尝试一下：

select datepart(hour,b.completion_time) Hour, count(*) NumberOfRecords
from billing b
group by datepart(hour,b.completion_time)

修改：

select  row_number() over (order by min(b.completion_time)) RowNumber, count(*) NumberOfRecords
from billing b
group by datepart(hour,b.completion_time)
order by min(b.completion_time)

Answer 2

尝试一下。

    Declare @StartTime DATETIME = '2016-04-16 23:50:23'
    Declare @EndTime DateTime = '2019-04-17 08:16:49'

    Declare @Tab Table(id int, Completion_Time DateTime)

    Insert into @Tab
    SELECT 1, '2016-04-16 23:50:23' Union All
    SELECT 2,'2016-04-17 00:50:24' Union All
    SELECT 3,'2016-04-17 01:50:26' Union All
    SELECT 4,'2016-04-17 01:50:32' Union All
    SELECT 5,'2016-04-17 01:50:55' Union All
    SELECT 6,'2016-04-17 02:50:28' Union All
    SELECT 7,'2016-04-17 02:50:30' Union All
    SELECT 8,'2016-04-17 02:50:45' Union All
    SELECT 9,'2016-04-17 04:50:32' Union All
    SELECT 10,'2016-04-17 04:50:52' 

    --Select Id, DATEDIFF(HH,@StartTime,Completion_Time) Diff from @Tab

    ;with cte
    As
    (

        SELECT CONVERT(VARCHAR(5),DATEDIFF(HH,@StartTime,Completion_Time)+1) as [Hour] , COUNT(*) As [Records]
        From @Tab
        Group by DATEDIFF(HH,@StartTime,Completion_Time)+1
    )

    Select  [Hour] + CASE
                WHEN [Hour] % 100 IN (11,12,13) THEN 'th'
                WHEN [Hour] % 10 = 1 THEN 'st'
                WHEN [Hour] % 10 = 2 THEN 'nd'
                WHEN [Hour] % 10 = 3 THEN 'rd'
                ELSE 'th' 
            END + ' hour',
        Records
    from cte

Answer 3

这将满足您的需求：

 SELECT HOUR(b.completion_time) hourOfDay, COUNT(*) NumberOfRecords
 FROM billing b 
 GROUP BY hourOfDay

HOUR是预定义的函数，用于根据DateTime计算小时。