CREATE OR REPLACE FUNCTION from_unixtime(integer) RETURNS timestamp AS '
SELECT
$1::abstime::timestamp without time zone AS result
' LANGUAGE 'SQL';

CREATE OR REPLACE FUNCTION unix_timestamp() RETURNS integer AS '
SELECT
ROUND(EXTRACT( EPOCH FROM abstime(now()) ))::int4 AS result;
' LANGUAGE 'SQL';

CREATE OR REPLACE FUNCTION unix_timestamp(timestamp with time zone) RETURNS integer AS '
SELECT
ROUND(EXTRACT( EPOCH FROM ABSTIME($1) ))::int4 AS result;
' LANGUAGE 'SQL';

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


CREATE FUNCTION FROM_UNIXTIME (
@timestamp integer
)
RETURNS datetime
AS
BEGIN
  /* Function body */
  DECLARE @return datetime

  SELECT @return = DATEADD(second, @timestamp,{d '1970-01-01'});

  RETURN @return
END