将日期时间转换为 Unix 时间戳

Question

In Microsoft SQL Server 2012 or above, is it possible to convert a datetime value to Unix time stamp in a single select statement? If so, how can it be done?

Answer 1

As Peter Halasz mentions in T-SQL DateTime to Unix Timestamp :

Converting a datetime to unix timestamp is easy, but involves error prone typing the following:

 @timestamp=DATEDIFF(second,{d '1970-01-01'},@datetime)

Where @datetime is the datetime value you want to convert. The {d 'yyyy-mm-dd'} notation is an ODBC escape sequence.

The function:

 CREATE FUNCTION UNIX_TIMESTAMP ( @ctimestamp datetime ) RETURNS integer AS BEGIN /* Function body */ declare @return integer SELECT @return = DATEDIFF(SECOND,{d '1970-01-01'}, @ctimestamp) return @return END

Try it out now like below @OA:

 SELECT UNIX_TIMESTAMP(GETDATE());

Answer 2

maybe this answer will help someone... If you have a problem when you try to convert datetime using datediff function to number of seconds (mssql message: The datediff function resulted in an overflow. The number of dateparts separating two date/time instances is too large. Try to use datediff with a less precise datepart.) then use:

select cast(datediff(d,'1970-01-01',@d1) as bigint)*86400+datediff(s,dateadd(day, datediff(day, 0, @d1), 0),@d1)

if you have ms sql server 2016+ use DATEDIFF_BIG function

Answer 3

my function with localization

CREATE FUNCTION UNIX_TIMESTAMP(@ctimestamp datetime)
RETURNS integer
AS
begin
  return DATEDIFF(second,'1970-01-01',GETUTCDATE())+datediff(second,GETDATE(),@ctimestamp)
end

then i use value in js code

new Date(unixSec*1000)