T-SQL DateTime to Unix Timestamp

This is a really simple Transact-SQL function to make it easier to convert MS SQL’s datetime datatype to Unix Timestamps.

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

That’s it :)

Try it out with:

SELECT UNIX_TIMESTAMP(GETDATE());