我正在做一些SQL选择查询,并希望将我的UTC日期时间列转换为本地时间,以便在我的查询结果中显示为本地时间。注意,我不希望通过代码进行这种转换,而是当我对我的数据库进行手动和随机SQL查询时。
当前回答
您必须重新格式化字符串以及转换为正确的时间。在这种情况下,我需要祖鲁时间。
Declare @Date datetime;
Declare @DateString varchar(50);
set @Date = GETDATE();
declare @ZuluTime datetime;
Declare @DateFrom varchar (50);
Declare @DateTo varchar (50);
set @ZuluTime = DATEADD(second, DATEDIFF(second, GETDATE(), GETUTCDATE()), @Date);
set @DateString = FORMAT(@ZuluTime, 'yyyy-MM-ddThh:mm:ssZ', 'en-US' )
select @DateString;
其他回答
下面的版本考虑了夏令时、UTC抵消,并且没有锁定到特定的年份。
---------------------------------------------------------------------------------------------------
--Name: udfToLocalTime.sql
--Purpose: To convert UTC to local US time accounting for DST
--Author: Patrick Slesicki
--Date: 3/25/2014
--Notes: Works on SQL Server 2008R2 and later, maybe SQL Server 2008 as well.
-- Good only for US States observing the Energy Policy Act of 2005.
-- Function doesn't apply for years prior to 2007.
-- Function assumes that the 1st day of the week is Sunday.
--Tests:
-- SELECT dbo.udfToLocalTime('2014-03-09 9:00', DEFAULT)
-- SELECT dbo.udfToLocalTime('2014-03-09 10:00', DEFAULT)
-- SELECT dbo.udfToLocalTime('2014-11-02 8:00', DEFAULT)
-- SELECT dbo.udfToLocalTime('2014-11-02 9:00', DEFAULT)
---------------------------------------------------------------------------------------------------
ALTER FUNCTION udfToLocalTime
(
@UtcDateTime AS DATETIME
,@UtcOffset AS INT = -8 --PST
)
RETURNS DATETIME
AS
BEGIN
DECLARE
@PstDateTime AS DATETIME
,@Year AS CHAR(4)
,@DstStart AS DATETIME
,@DstEnd AS DATETIME
,@Mar1 AS DATETIME
,@Nov1 AS DATETIME
,@MarTime AS TIME
,@NovTime AS TIME
,@Mar1Day AS INT
,@Nov1Day AS INT
,@MarDiff AS INT
,@NovDiff AS INT
SELECT
@Year = YEAR(@UtcDateTime)
,@MarTime = CONVERT(TIME, DATEADD(HOUR, -@UtcOffset, '1900-01-01 02:00'))
,@NovTime = CONVERT(TIME, DATEADD(HOUR, -@UtcOffset - 1, '1900-01-01 02:00'))
,@Mar1 = CONVERT(CHAR(16), @Year + '-03-01 ' + CONVERT(CHAR(5), @MarTime), 126)
,@Nov1 = CONVERT(CHAR(16), @Year + '-11-01 ' + CONVERT(CHAR(5), @NovTime), 126)
,@Mar1Day = DATEPART(WEEKDAY, @Mar1)
,@Nov1Day = DATEPART(WEEKDAY, @Nov1)
--Get number of days between Mar 1 and DST start date
IF @Mar1Day = 1 SET @MarDiff = 7
ELSE SET @MarDiff = 15 - @Mar1Day
--Get number of days between Nov 1 and DST end date
IF @Nov1Day = 1 SET @NovDiff = 0
ELSE SET @NovDiff = 8 - @Nov1Day
--Get DST start and end dates
SELECT
@DstStart = DATEADD(DAY, @MarDiff, @Mar1)
,@DstEnd = DATEADD(DAY, @NovDiff, @Nov1)
--Change UTC offset if @UtcDateTime is in DST Range
IF @UtcDateTime >= @DstStart AND @UtcDateTime < @DstEnd SET @UtcOffset = @UtcOffset + 1
--Get Conversion
SET @PstDateTime = DATEADD(HOUR, @UtcOffset, @UtcDateTime)
RETURN @PstDateTime
END
GO
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
declare @mydate2 datetime
set @mydate2=Getdate()
select @mydate2 as mydate,
dateadd(minute, datediff(minute,getdate(),@mydate2),getutcdate())
第一个功能:配置为意大利时区(+1,+2),切换日期:3月和10月的最后一个星期天,返回当前时区与datetime的差值作为参数。
Returns:
current timezone < parameter timezone ==> +1
current timezone > parameter timezone ==> -1
else 0
代码是:
CREATE FUNCTION [dbo].[UF_ADJUST_OFFSET]
(
@dt_utc datetime2(7)
)
RETURNS INT
AS
BEGIN
declare @month int,
@year int,
@current_offset int,
@offset_since int,
@offset int,
@yearmonth varchar(8),
@changeoffsetdate datetime2(7)
declare @lastweek table(giorno datetime2(7))
select @current_offset = DATEDIFF(hh, GETUTCDATE(), GETDATE())
select @month = datepart(month, @dt_utc)
if @month < 3 or @month > 10 Begin Set @offset_since = 1 Goto JMP End
if @month > 3 and @month < 10 Begin Set @offset_since = 2 Goto JMP End
--If i'm here is march or october
select @year = datepart(yyyy, @dt_utc)
if @month = 3
Begin
Set @yearmonth = cast(@year as varchar) + '-03-'
Insert Into @lastweek Values(@yearmonth + '31 03:00:00.000000'),(@yearmonth + '30 03:00:00.000000'),(@yearmonth + '29 03:00:00.000000'),(@yearmonth + '28 03:00:00.000000'),
(@yearmonth + '27 03:00:00.000000'),(@yearmonth + '26 03:00:00.000000'),(@yearmonth + '25 03:00:00.000000')
--Last week of march
Select @changeoffsetdate = giorno From @lastweek Where datepart(weekday, giorno) = 1
if @dt_utc < @changeoffsetdate
Begin
Set @offset_since = 1
End Else Begin
Set @offset_since = 2
End
End
if @month = 10
Begin
Set @yearmonth = cast(@year as varchar) + '-10-'
Insert Into @lastweek Values(@yearmonth + '31 03:00:00.000000'),(@yearmonth + '30 03:00:00.000000'),(@yearmonth + '29 03:00:00.000000'),(@yearmonth + '28 03:00:00.000000'),
(@yearmonth + '27 03:00:00.000000'),(@yearmonth + '26 03:00:00.000000'),(@yearmonth + '25 03:00:00.000000')
--Last week of october
Select @changeoffsetdate = giorno From @lastweek Where datepart(weekday, giorno) = 1
if @dt_utc > @changeoffsetdate
Begin
Set @offset_since = 1
End Else Begin
Set @offset_since = 2
End
End
JMP:
if @current_offset < @offset_since Begin
Set @offset = 1
End Else if @current_offset > @offset_since Set @offset = -1 Else Set @offset = 0
Return @offset
END
然后是转换日期的函数
CREATE FUNCTION [dbo].[UF_CONVERT]
(
@dt_utc datetime2(7)
)
RETURNS datetime
AS
BEGIN
declare @offset int
Select @offset = dbo.UF_ADJUST_OFFSET(@dt_utc)
if @dt_utc >= '9999-12-31 22:59:59.9999999'
set @dt_utc = '9999-12-31 23:59:59.9999999'
Else
set @dt_utc = (SELECT DATEADD(mi, DATEDIFF(mi, GETUTCDATE(), GETDATE()), @dt_utc) )
if @offset <> 0
Set @dt_utc = dateadd(hh, @offset, @dt_utc)
RETURN @dt_utc
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
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