Calculate Timezoneoffset using TimezoneName

Question

Hi All,

I am dealing with many timezones , I have a required to generate a SSRS report which uses the timezoneoffset based on the timezone name. The offset value returned should consider with or without DayLight Saving Time.

The input to the report is the date.

Can anyone please help me with the function to which i can pass date and it will return offset.

Input
Date: 2021-08-27
TimeZoneName- America/Chicago or Europe/Berlin

Output: Timezoneoffset -05/+1

Thanks.

Answer 1

In T-SQL, you can do as in this example_

DECLARE @tz nvarchar(100) = 'Pacific Standard Time'
SELECT datepart(tzoffset, sysutcdatetime() AT TIME ZONE @tz)

However, this requires that the names you have agree with those in the Windows registry, which is less likely. Rather you would have to Google around for a library to parse time-zone names, and all depending the source, you have to augment the solution you find.

Answer 2

Hi @SwapnilSalunke-4731,

Welcome to Microsoft Q&A!

Unfortunately SQL Server doesn't yet support IANA time zone identifiers (like America/Chicago) directly.

For now, the best option is to convert from the IANA identifier to a corresponding Windows time zone identifier in your application layer, and store that in your SQL Server.

Since your version is SQL Server 2012 which "AT TIME ZONE " does not work, you could refer below which is an alternative approach.

-- all SQL Server versions  
declare @utc_date datetime = getdate()  
select @utc_date as utc_time_zone,   
  dateadd(hh, datediff(hh, getutcdate(), getdate()), @utc_date) as local_time_zone  

In addition, it is also recommended to create and use a Calendar table.

Aaron Bertrand covers this exact scenario in depth here. You could refer it and find out more solutions.

Best regards,
Melissa

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