CODEWITHSUNDEEP
datetimesql-server-2008-r2timezone
Martijn
Martijn

Reputation: 12102

Compare local DateTime to DateTimeOffset

I have a database with a DateTime column, and want to compare it to some DateTimeOffset. The DateTime column is in (server) local time. There is nothing I can do about that apart from rant about the WTF'yness of it, which I like to do frequently and vehemently, so I can skip it here for now.

I'd like to be able to select all rows from the table where DateTime x happens before my DateTimeOffset. I can live with assuming that if it is DST on the server now, the DateTime column is also in DST and the other way around. These times will be localised around 'now', with the DateTime (almost) always being in the past few hours. I'll take the DST change on the chin when it happens, but the solution shouldn't be always wrong in either DST or non-DST.

As a bonus requirement, the table is large, so performing any manipulation on the DateTime is out of the question. What it comes down to I suppose is I'm looking for the equivalent of

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

could anyone help me making the magic happen?

Upvotes: 1

Views: 193

Answers (1)

Matt Johnson-Pint
Matt Johnson-Pint

Reputation: 241573

You'll need a SQL CLR function to do this. Inspired by this post, I wrote the following:

using System;
using Microsoft.SqlServer.Server;

public class UserDefinedFunctions
{
    [SqlFunction(IsDeterministic = false)]
    public static DateTime? ConvertDateTimeOffsetToLocalDateTime(DateTimeOffset? dto)
    {
        if (!dto.HasValue)
            return null;

        return dto.Value.ToLocalTime().DateTime;
    }
}

You can compile this yourself if you like, or just deploy it using the following, which contains the serialized binary and SQL deployment script:

EXEC sp_configure 'clr enabled', 1;
GO
RECONFIGURE
GO
CREATE ASSEMBLY [SqlClrDateTime]
FROM 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
WITH PERMISSION_SET = SAFE
GO
CREATE FUNCTION dbo.ConvertDateTimeOffsetToLocalDateTime(@dto datetimeoffset)
RETURNS datetime2
AS EXTERNAL NAME SqlClrDateTime.UserDefinedFunctions.ConvertDateTimeOffsetToLocalDateTime
GO

And here is how you can use it in your scenario:

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

DECLARE @dt datetime = dbo.ConvertDateTimeOffsetToLocalDateTime(@dto) 

SELECT * FROM MyTable WHERE datetimecol < @dt

Upvotes: 1

Related Questions