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
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
其他回答
最简单的答案并不总是在底部,但这一次是,并且可以在上面的评论中看到。 使用您自己的“AT TIME ZONE”来捕获列/数据字段的TzOffset,而不是当前的SYSDATETIME。 在下面的数据中,2个查询,一个关于feb数据(DST是关闭的,在阿姆斯特丹的冬天)+1差异 第二次查询阿姆斯特丹4月份的数据,所以+2小时的差异。
select top 2 month(receiveTimeUTC) as MonthInWinterOrSpring
, receiveTimeUTC
, CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset, receiveTimeUTC), DATENAME(TzOffset, SYSDATETIMEOFFSET()))) as LocalTimeWrongNoDST
, CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset, receiveTimeUTC), DATENAME(TzOffset, receiveTimeUTC AT TIME ZONE 'Central European Standard Time' ))) as LocalTimeWithDST
from sensordetails order by id
select top 2 month(receiveTimeUTC) as MonthInWinterOrSpring, receiveTimeUTC
, CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset, receiveTimeUTC), DATENAME(TzOffset, SYSDATETIMEOFFSET()))) as LocalTimeWrongNoDST
, CONVERT(datetime, SWITCHOFFSET(CONVERT(datetimeoffset, receiveTimeUTC), DATENAME(TzOffset, receiveTimeUTC AT TIME ZONE 'Central European Standard Time' ))) as LocalTimeWithDST
from sensordetails order by id desc
结果:
所以这是一个T-SQL (SQL Server Answer),不需要函数的storedproc。
这很简单。试试这个Azure SQL Server:
SELECT YourDateTimeColumn AT TIME ZONE 'Eastern Standard Time' FROM YourTable
对于本地SQL Server:
SELECT CONVERT(datetime2, SWITCHOFFSET(CONVERT(datetimeoffset, gETDATE()), DATENAME(TzOffset, gETDATE() AT TIME ZONE 'Eastern Standard Time'))) FROM YourTable
UNIX时间戳只是一个特定日期和UNIX纪元之间的秒数,
SELECT DATEDIFF(SECOND,{d '1970-01-01'},GETDATE()) //返回SQL server中的UNIX时间戳
你可以创建一个函数,使用Country Offset将本地日期时间转换为Unix UTC SQL server中的Unix时间戳函数
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
对于任何仍然试图解决这个问题的人,这里有一个在SQL Server 2017中工作的概念证明
declare
@StartDate date = '2020-01-01'
;with cte_utc as
(
select
1 as i
,CONVERT(datetime, @StartDate) AS UTC
,datepart(weekday, CONVERT(datetime, @StartDate)) as Weekday
,datepart(month, CONVERT(datetime, @StartDate)) as [Month]
,datepart(YEAR, CONVERT(datetime, @StartDate)) as [Year]
union all
Select
i + 1
,dateadd(d, 1, utc)
,datepart(weekday, CONVERT(datetime, dateadd(d, 1, utc))) as Weekday
,datepart(month, CONVERT(datetime, dateadd(d, 1, utc))) as [Month]
,datepart(YEAR, CONVERT(datetime, dateadd(d, 1, utc))) as [Year]
from
cte_utc
where
(i + 1) < 32767
), cte_utc_dates as
(
select
*,
DENSE_RANK()OVER(PARTITION BY [Year], [Month], [Weekday] ORDER BY Utc) WeekDayIndex
from
cte_utc
), cte_hours as (
select 0 as [Hour]
union all
select [Hour] + 1 from cte_hours where [Hour] < 23
)
select
d.*
, DATEADD(hour, h.Hour, d.UTC) AS UtcTime
,CONVERT(datetime, DATEADD(hour, h.Hour, d.UTC) AT TIME ZONE 'UTC' AT TIME ZONE 'Central Standard Time') CST
,CONVERT(datetime, DATEADD(hour, h.Hour, d.UTC) AT TIME ZONE 'UTC' AT TIME ZONE 'Eastern Standard Time') EST
from
cte_utc_dates d, cte_hours h
where
([Month] = 3 and [Weekday] = 1 and WeekDayIndex = 2 )-- dst start
or
([Month] = 11 and [Weekday] = 1 and WeekDayIndex = 1 )-- dst end
order by
utc
OPTION (MAXRECURSION 32767)
GO
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