在单个表格中,我说我有里程和时间戳的记录。我想得到每天和每小时的平均里程数。由于日期格式,我不能使用固有的“Group By”子句。
以下是一些示例数据:
Table: tb_mileage
===============================================
f_mileagetimestamp f_mileage
-----------------------------------------------
2014-08-11 11:13:02.000 50
2014-08-11 16:12:55.000 100
2014-08-11 16:55:00.000 30
2014-08-12 11:12:50.000 80
2014-08-12 16:12:49.000 100
2014-08-13 08:12:46.000 40
2014-08-13 08:45:31.000 100
因此,理想的结果集如下所示( PER DAY )(注意,日期格式无关紧要):
Date Average
------------------------------------------------
08/11/2014 60
08/12/2014 90
08/13/2014 70
理想的结果集如下所示( PER HOUR )(注意,日期格式无关紧要):
Date Average
------------------------------------------------
08/11/2014 11:00:00 50
08/11/2014 16:00:00 65
08/12/2014 11:00:00 80
08/12/2014 16:00:00 100
08/13/2014 08:00:00 70
请注意,此处的示例纯粹是理论上的和简化的,并不一定反映实际实施所需的确切标准。这仅仅是为了推动我自己的学习,因为我发现做类似事情的所有例子都非常复杂,使学习变得困难。
答案 0 :(得分:6)
请尝试使用日期版本。
select cast(t.f_mileagetimestamp as date) as dt, avg(t.f_mileage) as avg_mileage
from
tb_mileage t
group by cast(t.f_mileagetimestamp as date)
order by cast(t.f_mileagetimestamp as date) asc;
对于小时版本,您可以使用此功能。
select t2.dt, avg(t2.f_mileage) as avg_mileage
from
(
select substring(CONVERT(nvarchar(100), t1.f_mileagetimestamp, 121), 1, 13) + ':00' as dt, t1.f_mileage
from
tb_mileage t1
) t2
group by t2.dt
order by t2.dt asc;
答案 1 :(得分:5)
我认为这应该适用于" day"版本:
select cast(f_mileagetimestamp as date), avg(f_mileage)
from tb_mileage
group by cast(f_mileagetimestamp as date)
order by cast(f_mileagetimestamp as date);
小时,我只会使用这个功能:
select cast(f_mileagetimestamp as date), datepart(hour, f_mileagetimestamp), avg(f_mileage)
from tb_mileage
group by cast(f_mileagetimestamp as date), datepart(hour, f_mileagetimestamp)
order by cast(f_mileagetimestamp as date), datepart(hour, f_mileagetimestamp);