Question

我有一个包含列的表：

ID_LOG (this is the pk) | TS (type=datetime) | VALUE (type=double) | ID_CHANNEL (unique).

此表每15分钟从不同的频道记录值。这些值来自一些计数器，因此它们总是在增加现在我想得到特定频道去年每一天的最大值和最小值（所以净差额）之间的差异。
类似的东西：

SELECT MAX(T1.value) - MIN(T1.value), T1.ts
FROM dbo.[LOG] as T1
WHERE T1.ts > DATEADD(year, -1, GETDATE()) and
T1.ID_CHANNEL=x      //[x being the channel i want]
GROUP BY SOMEDATEFUNCITON(T1.ts) //[SOMEDATEFUNCTION is the function that groups results by date not taking in consideration the time of timestamp but only year-month-day]

我不关心效率，因为我每年只会做一次或两次查询。这可能吗？你怎么做？非常感谢！

Answer 1

您可以使用CAST(T1.ts AS DATE)截断时间戳。替换你拥有的东西：

SELECT MAX(T1.valore) - MIN(T1.valore), CAST(T1.ts AS DATE)
...
GROUP BY CAST(T1.ts AS DATE)

_{虽然根据您的架构，TS已经DATE，所以您不需要这样做。您是否要告诉我们TS是DATETIME？}

Answer 2

SELECT convert(char(10), creationDate, 120), COUNT(custID) AS totalRegistered
FROM dbo.SecureSignInUser
WHERE (CreationDate BETWEEN '11/1/2004' AND '11/30/2004'

GROUP BY convert(char(10), creationDate, 120)

检查这个日期格式.. http://msdn.microsoft.com/en-us/library/ms187928.aspx

根据您的数据库日期格式转换/转换您的函数返回日期值格式。

按日期汇总sql server 2005

2 个答案: