SQL Server - Convert date field to UTC

Question

I have recently updated my system to record date/times as UTC as previously they were storing as local time.

I now need to convert all the local stored date/times to

Answer 1

We can convert ServerZone DateTime to UTC and UTC to ServerZone DateTime

Simply run the following scripts to understand the conversion then modify as what you need

--Get Server's TimeZone
DECLARE @ServerTimeZone VARCHAR(50)
EXEC MASTER.dbo.xp_regread 'HKEY_LOCAL_MACHINE',
'SYSTEM\CurrentControlSet\Control\TimeZoneInformation',
'TimeZoneKeyName',@ServerTimeZone OUT

-- ServerZone to UTC DATETIME
DECLARE @CurrentServerZoneDateTime DATETIME = GETDATE()
DECLARE @UTCDateTime  DATETIME =  @CurrentServerZoneDateTime AT TIME ZONE @ServerTimeZone AT TIME ZONE 'UTC' 
--(OR)
--DECLARE @UTCDateTime  DATETIME = GETUTCDATE()
SELECT @CurrentServerZoneDateTime AS CURRENTZONEDATE,@UTCDateTime AS UTCDATE

-- UTC to ServerZone DATETIME
SET @CurrentServerZoneDateTime = @UTCDateTime AT TIME ZONE 'UTC' AT TIME ZONE @ServerTimeZone
SELECT @UTCDateTime AS UTCDATE,@CurrentServerZoneDateTime AS CURRENTZONEDATE

Note: This(AT TIME ZONE) working on only SQL Server 2016+ and this advantage is automatically considering Daylight while converting to particular Time zone