按日期和总和数据选择数据 - SQL Server 2005

Question

我来自MySQL并试图在SQL Server 2005上编写T-SQL代码，我发现它完全不同。

这是我想要做的事情（使用MySQL）

select sum(datapoint) as sum, date(mytimestamp) as date
from datalog
where datapoint = '27'
group by date

即。获取按日期汇总和分组的数据列表。

Answer 1

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在标记sql server 2008时回答

select sum(datapoint) as [sum], CAST(mytimestamp AS DATE) as [date]
from datalog
where datapoint = '27'
group by CAST(mytimestamp AS DATE)

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对于SQL Server 2005

SELECT   CONVERT(VARCHAR(11), timestamp, 111) DATE, 
         SUM(datapoint) totalDatapoint
FROM     table1
GROUP BY CONVERT(VARCHAR(11), timestamp, 111)
ORDER BY DATE ASC

SQLFiddle Demo

Answer 2

转换为varchar不是一个好的解决方案，只需从时间戳中删除时间部分，然后将其分组：

select sum(datapoint) as sum, dateadd(d, 0, datediff(d, 0, mytimestamp)) as date
from datalog
where datapoint = '27'
group by datediff(d, 0, mytimestamp)