How to convert a DateTime string to a DateTime in

问题:

I have a DateTime varchar in this format: 2005-08-08T00:00:00+01:00.

1. Does this format have a name? (it's not ISO8601. Is it RFC3339?)
2. How can I convert it to a DateTime using Transact-Sql?

EDIT Here's a summary answer, cobbled together from others input:

1. It is ISO8601 with a time offset from UTC. If it was UTC it would end with a 'Z' instead of '+01:00'. wikipedia

2. You can convert it to local time or to utc as follows:

   DECLARE @d VARCHAR(25) SET @d = '2007-08-08T00:01:00+01:00' SET @d = '2007-08-08T00:01:00-01:00' SET @d = '2007-08-08T00:01:00+05:30'

   SELECT @d as Input, CONVERT(DATETIME, LEFT(@d, 19), 126) AS LocalDate , DATEADD(MINUTE , -CAST((SUBSTRING(@d, 20, 1) + RIGHT(@d, 2)) AS INT) , DATEADD(HOUR ,-CAST(SUBSTRING(@d, 20, 3) AS INT) , CONVERT(DATETIME, LEFT(@d, 19), 126))) as UtcDate WHERE @d LIKE '_--_T__::[+-]:'

Results:

Input                     LocalDate               UtcDate
------------------------- ----------------------- -----------------------
2007-08-08T00:01:00+01:00 2007-08-08 00:01:00.000 2007-08-07 23:01:00.000

2007-08-08T00:01:00-01:00 2007-08-08 00:01:00.000 2007-08-08 01:01:00.000

2007-08-08T00:01:00+05:30 2007-08-08 00:01:00.000 2007-08-07 18:31:00.000

回答1:

In SQL Server 2008 you can use the datetimeoffset data type.

SELECT [Result] = CONVERT(datetimeoffset, '2005-08-08T00:01:00+01:00', 127)

Output:

Result
----------------------------------
2005-08-08 00:01:00.0000000 +01:00

---

In SQL Server 2005 and earlier you can compute the UTC date and offset:

SELECT [LocalDate], [OffsetMinutes], [UtcDate]
FROM
(
    SELECT [IsoDate] = '2007-08-08T00:01:00+01:00'
) A
OUTER APPLY
(
    SELECT [LocalDate] = CONVERT(datetime, LEFT([IsoDate], 19), 126)
    , [OffsetMinutes] =
        CASE SUBSTRING([IsoDate], 20, 1)
            WHEN '+' THEN +1
            WHEN '-' THEN -1
        END
        * DATEDIFF(minute, 0,
            CAST(SUBSTRING([IsoDate], 21, 5) + ':00' AS datetime))
    WHERE [IsoDate] LIKE '____-__-__T__:__:__[+-]__:__'
) B
OUTER APPLY
(
    SELECT [UtcDate] = DATEADD(minute, -[OffsetMinutes], [LocalDate])
) C

Output:

LocalDate               OffsetMinutes UtcDate
----------------------- ------------- -----------------------
2007-08-08 00:01:00.000 60            2007-08-07 23:01:00.000

回答2:

You can do it a really ugly way, where you get the date first, then get the time and add the offset as hour:

declare @d varchar(50)
set @d = '2005-08-08T00:00:00+01:00'

select Convert(datetime, left(@d, 10)) 
    + DateAdd(hour, Cast(substring(@d, 21, 2) as int), convert(datetime, substring(@d, 12, 8)))

or a consolidated version:

SELECT DateAdd(hour, Cast(substring(@d, 21, 2) as int), CONVERT(datetime, LEFT(@d, 19) ,127))

Final Result:
2005-08-08 01:00:00.000

if you don't need the offset, then:

declare @d varchar(50)
set @d = '2005-08-08T00:00:00+01:00'

select Convert(datetime, left(@d, 10)) 
    +  convert(datetime, substring(@d, 12, 8))

Result:
2005-08-08 00:00:00.000

回答3:

Its ISO8601 with time zone Z

use

SELECT CONVERT(datetime,'2005-08-08T00:00:00',126)

see MSDN Explanation

EDIT: I think it something to do with the zone on the end I originally assumed tSql would accept that but turns out it wont.

回答4:

Per the selected answer, datetimeoffset is a good solution. However, be careful sql server side with built in functions. (I tried to paste this as a comment to the accepted answer, but it would not format the code sample)

select GETDATE(), CONVERT(datetimeoffset, GETDATE(), 127), CONVERT(varchar, convert(datetimeoffset, getdate(), 127)) 
-- Ugg! a SQL Server Bug!!!
-- 2013-08-16 12:54:54.090  2013-08-16 12:54:54.0900000 +00:00  2013-08-16 12:54:54.0900000 +0

select GETUTCDATE(),convert( datetimeoffset, GETUTCDATE(), 127), convert(varchar, convert( datetimeoffset, GETUTCDATE(), 127)) 
-- 2013-08-16 16:54:54.090  2013-08-16 16:54:54.0900000 +00:00  2013-08-16 16:54:54.0900000 +0