T-SQL組按日期而不是日期時間

Question

select [DateTime (UTC)], 
sum([messages sent external]) as 'messages sent external', 
sum([messages sent internal]) as 'messages sent internal', 
sum([messages received external]) as 'messages received external', 
sum([messages received internal]) as 'messages received internal', 
max([Message Latency Internal High]) as 'Message Latency Internal High', 
max([Message Latency Internal Avg]) as 'Message Latency Internal Avg' from dbo.Monthly_MailFlowStats_2014_03 group by [DateTime (UTC)] order by [DateTime (UTC)] asc 

結果顯示datetime中每天每小時的所有數據。我是否可以將日期時間修剪爲日期，以便結果顯示當天的數據而不是一天中的小時？

This: 
2014-03-01 

instead of: 
2014-03-01 00:00:00.000 
2014-03-01 01:00:00.000 
2014-03-01 02:00:00.000 

Answer 1

select cast([DateTime (UTC)] AS date) AS [Date], 
sum([messages sent external]) as 'messages sent external', 
sum([messages sent internal]) as 'messages sent internal', 
sum([messages received external]) as 'messages received external', 
sum([messages received internal]) as 'messages received internal', 
max([Message Latency Internal High]) as 'Message Latency Internal High', 
max([Message Latency Internal Avg]) as 'Message Latency Internal Avg' 
from dbo.Monthly_MailFlowStats_2014_03 
group by cast([DateTime (UTC)] AS date) 
order by [Date] asc 

Answer 2

假設你的SQL Server 2008+上：

select 
    CAST([DateTime (UTC)] AS DATE) AS 'Date (UTC)', 
    sum([messages sent external]) as 'messages sent external', 
    sum([messages sent internal]) as 'messages sent internal', 
    sum([messages received external]) as 'messages received external', 
    sum([messages received internal]) as 'messages received internal', 
    max([Message Latency Internal High]) as 'Message Latency Internal High', 
    max([Message Latency Internal Avg]) as 'Message Latency Internal Avg' 
from 
    dbo.Monthly_MailFlowStats_2014_03 
group by 
    CAST([DateTime (UTC)] AS DATE) 
order by 
    [DateTime (UTC)] asc 

Answer 3

當然，剛剛修剪時間部分關閉：

select DATEADD(dd, DATEDIFF(dd, 0, [DateTime (UTC)]), 0) [DateTime (UTC)], 
    sum([messages sent external]) as 'messages sent external', 
    sum([messages sent internal]) as 'messages sent internal', 
    sum([messages received external]) as 'messages received external', 
    sum([messages received internal]) as 'messages received internal', 
    max([Message Latency Internal High]) as 'Message Latency Internal High', 
    max([Message Latency Internal Avg]) as 'Message Latency Internal Avg' 
from dbo.Monthly_MailFlowStats_2014_03 
group by DATEADD(dd, DATEDIFF(dd, 0, [DateTime (UTC)]), 0) 
order by [DateTime (UTC)] asc 

注意，有幾種方法可以剪掉日期的時間部分;這只是其中之一