比较本地DateTime和DateTimeOffset

我有一个带有DateTime列的数据库，希望将其与某个DateTimeOffset进行比较。DateTime列为（服务器）本地时间。我对此无能为力，除了对WTF的缺点大喊大叫，我喜欢频繁而激烈地这样做，所以我现在可以跳过这里

我希望能够从表中选择DateTime x发生在DateTimeOffset之前的所有行。我可以接受这样的假设：如果现在服务器上是DST，那么DateTime列也在DST中，反之亦然。这些时间将定位在“现在”，日期时间（几乎）总是在过去的几个小时内。当DST发生变化时，我会对下巴进行调整，但解决方案在DST或非DST中都不应该总是错误的

作为额外要求，表很大，因此不可能对DateTime执行任何操作。归根结底，我想我是在寻找

DECLARE @dto datetimeoffset(4) = '12-10-25 12:32:10 +06:00';

DECLARE @dt datetime = --this is where the magic happens?

SELECT * FROM MyTable WHERE datetimecol < @dt

DECLARE@dto datetimeoffset（4）='12-10-25 12:32:10+06:00'；
声明@dt datetime=--这就是神奇发生的地方？
从datetimecol<@dt所在的MyTable中选择*

---

有谁能帮我实现这个神奇的过程吗？

您需要一个SQL CLR函数来实现这一点。受此启发，我写了以下内容：

使用系统；
使用Microsoft.SqlServer.Server；
公共类UserDefinedFunctions
{
[SqlFunction（IsDeterministic=false）]
公共静态日期时间？ConvertDateTimeOffsetToLocalDateTime（DateTimeOffset？dto）
{
如果（！dto.HasValue）
返回null；
返回dto.Value.ToLocalTime（）.DateTime；
}
}

如果愿意，您可以自己编译此脚本，也可以使用包含序列化二进制和SQL部署脚本的以下脚本进行部署：

EXEC sp_配置'clr enabled'，1；
去
重新配置
去
创建程序集[SqlClrDateTime]
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