休眠-两个日期之间的差额

Question

我如何计算两个日期之间的差异，以使查询与：MySql，H2和SqlServer兼容？

Answer 1

• SQL Server - you can use DATEDIFF function that returns difference in specified DATEPART

SELECT DATEDIFF(dd,'1/20/2014,'1/22/2014')

http://technet.microsoft.com/en-us/library/ms189794.aspx

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• MySQL - DATEDIFF() just a little bit differently,

SELECT DATEDIFF('2008-11-30','2008-11-29') AS DiffDate

http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_datediff

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• H2 - DATEDIFF

DATEDIFF('YEAR', T1.CREATED, T2.CREATED)

http://www.h2database.com/html/functions.html#datediff

Answer 2

在SQL Server中-

  datediff (day,startdate,enddate)