EXECUTE BLOCK
RETURNS
(
  ret TIMESTAMP WITH TIME ZONE,
  disp_hour SMALLINT,
  disp_minute SMALLINT
)
AS
  DECLARE VARIABLE tmstmp_notz TIMESTAMP WITHOUT TIME ZONE;
BEGIN
  tmstmp_notz = CURRENT_TIMESTAMP AT TIME ZONE 'Asia/Krasnoyarsk';
  ret = tmstmp_notz;
  disp_hour = Extract(TIMEZONE_HOUR FROM ret);
  disp_minute = Extract(TIMEZONE_MINUTE FROM ret);
  SUSPEND;
  ret = tmstmp_notz AT TIME ZONE 'UTC';
  disp_hour = Extract(TIMEZONE_HOUR FROM ret);
  disp_minute = Extract(TIMEZONE_MINUTE FROM ret);
  SUSPEND;
  ret = tmstmp_notz AT TIME ZONE 'Asia/Krasnoyarsk';
  disp_hour = Extract(TIMEZONE_HOUR FROM ret);
  disp_minute = Extract(TIMEZONE_MINUTE FROM ret);
  SUSPEND;
  ret = tmstmp_notz AT TIME ZONE 'Europe/Moscow';
  disp_hour = Extract(TIMEZONE_HOUR FROM ret);
  disp_minute = Extract(TIMEZONE_MINUTE FROM ret);
  SUSPEND;
  ret = tmstmp_notz AT LOCAL;
  disp_hour = Extract(TIMEZONE_HOUR FROM ret);
  disp_minute = Extract(TIMEZONE_MINUTE FROM ret);
  SUSPEND;
END

SELECT Cast('0001-01-01 00:00:00.100 UTC' AS TIMESTAMP WITH TIME ZONE) AT TIME ZONE 'Europe/Moscow'
  FROM oneRow

SELECT Extract(HOUR FROM Cast(
      '0001-01-01 00:00:00.100 UTC' AS TIMESTAMP WITH TIME ZONE
    ) AT TIME ZONE 'Europe/Moscow')
  FROM oneRow

SELECT Cast('0001-01-01 00:00:00.100' AS TIMESTAMP WITHOUT TIME ZONE) FROM oneRow

EXECUTE BLOCK
  RETURNS
  (
    dayz_chk BIGINT,
    dayz DOUBLE PRECISION,
    ahead_chk TIMESTAMP WITHOUT TIME ZONE,
    back_chk TIMESTAMP WITHOUT TIME ZONE
  )
AS
  DECLARE VARIABLE ts TIMESTAMP WITHOUT TIME ZONE;
BEGIN
  ts = Cast('Now' AS TIMESTAMP WITHOUT TIME ZONE);
  dayz_chk = DATEDIFF(DAY
      FROM Cast('0001-01-01 00:00:00.100' AS TIMESTAMP WITHOUT TIME ZONE)
      TO ts);
  dayz = Cast(DATEDIFF(MILLISECOND
      FROM Cast('0001-01-01 00:00:00.100' AS TIMESTAMP WITHOUT TIME ZONE)
      TO ts AT TIME ZONE 'UTC') AS DOUBLE PRECISION) / 86400000;
  ahead_chk = '0001-01-01 00:00:00.100';
  ahead_chk = ahead_chk + dayz;
  back_chk = ts - dayz;
  SUSPEND;
END

  dayz = Cast(DATEDIFF(MILLISECOND
      FROM Cast('0001-01-01 00:00:00.100' AS TIMESTAMP WITHOUT TIME ZONE)
      TO ts AT TIME ZONE 'UTC') AS DOUBLE PRECISION) / 86400000;

SET TIME ZONE 'UTC';
SELECT Cast(1 AS BIGINT) AS seq, CURRENT_TIMESTAMP FROM oneRow
UNION SELECT 2, Cast('Now' AS TIMESTAMP WITH TIME ZONE) FROM oneRow;