How to calculate the difference between two timestamps in a given component unit using the TIMESTAMPDIFF() function?

TIMESTAMPDIFF(unit, to_time, from_time) is a MySQL built-in function that calculates the difference from one timestamp to another in a given component unit. For example:

SELECT TIMESTAMPDIFF(DAY, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002');
  -- +-------------------------------------------------------------------------+
  -- | TIMESTAMPDIFF(DAY, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002') |
  -- +-------------------------------------------------------------------------+
  -- |                                                                      -1 |
  -- +-------------------------------------------------------------------------+

SELECT TIMESTAMPDIFF(HOUR, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002');
  -- +--------------------------------------------------------------------------+
  -- | TIMESTAMPDIFF(HOUR, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002') |
  -- +--------------------------------------------------------------------------+
  -- |                                                                      -46 |
  -- +--------------------------------------------------------------------------+

SELECT TIMESTAMPDIFF(SECOND, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002');
  -- +----------------------------------------------------------------------------+
  -- | TIMESTAMPDIFF(SECOND, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002') |
  -- +----------------------------------------------------------------------------+
  -- |                                                                    -169137 |
  -- +----------------------------------------------------------------------------+

SELECT TIMESTAMPDIFF(MICROSECOND, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002');
  -- +---------------------------------------------------------------------------------+
  -- | TIMESTAMPDIFF(MICROSECOND, '2028-12-31 23:59:59', '2028-12-30 01:01:01.000002') |
  -- +---------------------------------------------------------------------------------+
  -- |                                                                   -169137999998 |
  -- +---------------------------------------------------------------------------------+

SELECT TIMEDIFF('2028-12-31 23:59:59', '2029-01-01 01:01:01.000002');
  -- +---------------------------------------------------------------+
  -- | TIMEDIFF('2028-12-31 23:59:59', '2029-01-01 01:01:01.000002') |
  -- +---------------------------------------------------------------+
  -- | -01:01:02.000002                                              |
  -- +---------------------------------------------------------------+

SELECT DATEDIFF('2028-12-31 23:59:59', '2029-01-01 01:01:01.000002');
  -- +---------------------------------------------------------------+
  -- | DATEDIFF('2028-12-31 23:59:59', '2029-01-01 01:01:01.000002') |
  -- +---------------------------------------------------------------+
  -- |                                                            -1 |
  -- +---------------------------------------------------------------+

Reference information of the TIMESTAMPDIFF() function:

TIMESTAMPDIFF(unit, to_time, from_time): int
  Subtracts to_time from from_time and returns the difference
  as an integer for the given unit, which should be one of the
  following values: MICROSECOND, SECOND, MINUTE, HOUR, DAY, WEEK,
  MONTH, QUARTER, or YEAR.

Arguments, return value and availability:
  unit: Required. The timestamp component unit for the result.
  to_time: Required. The timestamp to be subtracted.
  from_time: Required. The timestamp to be subtracted from.
  int: Return value. The difference as an integer for the given unit.
  Available since MySQL 4.

Related MySQL functions:

• DATEDIFF() - Difference of Two Dates
• TIMEDIFF() - Difference of Two Timestamps

⇒ TIME_FORMAT() - Formatting Time

⇐ TIMESTAMPADD() - Incrementing Timestamp

⇑ MySQL Functions on Date and Time

⇑⇑ MySQL Function References