下面是一个将夏令时考虑在内的更简单的例子

CREATE FUNCTION [dbo].[UtcToLocal] 
(
    @p_utcDatetime DATETIME 
)
RETURNS DATETIME
AS
BEGIN
    RETURN DATEADD(MINUTE, DATEDIFF(MINUTE, GETUTCDATE(), @p_utcDatetime), GETDATE())
END

这些对我来说都没用，但下面这个100%有效。希望这能帮助其他像我一样尝试转换它的人。

CREATE FUNCTION [dbo].[fn_UTC_to_EST]
(
    @UTC datetime,
    @StandardOffset int
)
RETURNS datetime
AS
BEGIN

declare 
    @DST datetime,
    @SSM datetime, -- Second Sunday in March
    @FSN datetime  -- First Sunday in November
-- get DST Range
set @SSM = DATEADD(dd,7 + (6-(DATEDIFF(dd,0,DATEADD(mm,(YEAR(GETDATE())-1900) * 12 + 2,0))%7)),DATEADD(mm,(YEAR(GETDATE())-1900) * 12 + 2,0))+'02:00:00' 
set @FSN = DATEADD(dd, (6-(DATEDIFF(dd,0,DATEADD(mm,(YEAR(GETDATE())-1900) * 12 + 10,0))%7)),DATEADD(mm,(YEAR(GETDATE())-1900) * 12 + 10,0)) +'02:00:00'

-- add an hour to @StandardOffset if @UTC is in DST range
if @UTC between @SSM and @FSN
    set @StandardOffset = @StandardOffset + 1

-- convert to DST
set @DST = dateadd(hour,@StandardOffset,@UTC)

-- return converted datetime
return @DST

END

使用新的SQL Server 2016机会:

CREATE FUNCTION ToLocalTime(@dtUtc datetime, @timezoneId nvarchar(256))
RETURNS datetime
AS BEGIN

return @dtUtc AT TIME ZONE 'UTC' AT TIME ZONE @timezoneId

/* -- second way, faster

return SWITCHOFFSET(@dtUtc , DATENAME(tz, @dtUtc AT TIME ZONE @timezoneId))

*/

/* -- third way

declare @dtLocal datetimeoffset
set @dtLocal = @dtUtc AT TIME ZONE @timezoneId
return dateadd(minute, DATEPART (TZoffset, @dtLocal), @dtUtc)

*/

END
GO

但clr程序的工作速度快5倍:'-(

请注意，一个时区的偏移量可以更改为冬季时间或夏季时间。例如

select cast('2017-02-08 09:00:00.000' as datetime) AT TIME ZONE 'Eastern Standard Time'
select cast('2017-08-08 09:00:00.000' as datetime) AT TIME ZONE 'Eastern Standard Time'

结果:

2017-02-08 09:00:00.000 -05:00
2017-08-08 09:00:00.000 -04:00

你不能只是添加常数偏移量。

下面是一个将夏令时考虑在内的更简单的例子

CREATE FUNCTION [dbo].[UtcToLocal] 
(
    @p_utcDatetime DATETIME 
)
RETURNS DATETIME
AS
BEGIN
    RETURN DATEADD(MINUTE, DATEDIFF(MINUTE, GETUTCDATE(), @p_utcDatetime), GETDATE())
END

对甲骨文来说最好的方法:

硬编码的datetime:

SELECT TO_CHAR(CAST((FROM_TZ(CAST(TO_DATE('2018-10-27 21:00', 'YYYY-MM-DD HH24:MI') AS TIMESTAMP), 'UTC') AT  TIME ZONE 'EET') AS DATE), 'YYYY-MM-DD HH24:MI') UTC_TO_EET FROM DUAL

结果: 2018-10-28 00:00

列名和表名:

SELECT TO_CHAR(CAST((FROM_TZ(CAST(COLUMN_NAME AS TIMESTAMP), 'UTC') AT  TIME ZONE 'EET') AS DATE), 'YYYY-MM-DD HH24:MI') UTC_TO_EET FROM TABLE_NAME

这样就可以获得与夏令时同步的服务器时间

declare @dt datetime
set @dt = getutcdate() -- GMT equivalent

sysdatetimeoffset会考虑夏令时

select [InputTime] = @dt
       , [LocalTime2] = dateadd(mi, datediff(mi, sysdatetimeoffset(),getdate()), @dt)