TimeZone使用TSQL進行轉換

Question

我有每小時傳入數據（跨越5年），並且在CST或EST中記錄了時間戳。我想以UTC時間將它存儲在我的數據庫中。

有沒有辦法讓我使用TSQL從CST/CDT/CPT或EST/EDT/EPT轉換爲UTC？

Answer 1

可以確定爲datetime在行EST或EDT：

Since 2007, the local time changes at 02:00 EST to 03:00 EDT on the second Sunday in March and returns at 02:00 EDT to 01:00 EST on the first Sunday in November, in the U.S. as well as in Canada。

然後申請DATEADD()

MB我的源代碼更好地解釋我的意思：

declare @t table(dt datetime) 

insert @t values ('2011-07-06T10:00:00'), ('2011-01-01T00:00:00'), ('2011-03-12T00:00:00'), 
    ('2006-07-06T10:00:00') 

select b.dt 
    , CASE 
     WHEN b.dt between b.[edt_start] and [edt_end] 
      THEN DATEADD(HH, -5, b.dt) 
     ELSE DATEADD(HH, -4, b.dt) 
    END 

    , CASE 
     WHEN b.dt between b.[edt_start] and [edt_end] 
      THEN '-05:00' 
     ELSE '-04:00' 
    END 

from 
(
    select a.dt 
     , DATEADD(HH, 2, CASE 
      WHEN DATEPART(WEEKDAY, a.march) = 1 
       THEN a.march 
      ELSE DATEADD(DAY, 15 - DATEPART(WEEKDAY, a.march), a.march) 
     END) [edt_start] 

     , DATEADD(HH, 2, CASE 
      WHEN DATEPART(WEEKDAY, a.november) = 1 
       THEN a.march 
      ELSE DATEADD(DAY, 8 - DATEPART(WEEKDAY, a.november), a.november) 
     END) [edt_end] 
    from 
    (
     select t.dt 
      , YEAR(t.dt) [year] 
      , CAST(CAST(YEAR(t.dt) as varchar(4)) + '03' + '01' as datetime) [march] 
      , CAST(CAST(YEAR(t.dt) as varchar(4)) + '11' + '01' as datetime) [november] 
     from @t t 
    )a 
)b 

Answer 2

的mI建議您存儲這些爲DATETIMEOFFSET保存時區信息。

如果你需要顯示的那麼作爲UTC日期，那麼你可以使用SWITCHOFFSET