TIMESTAMP

A timestamp. The range is '1970-01-01 00:00:00' to partway through the
year 2037.

A TIMESTAMP column is useful for recording the date and time of an
INSERT or UPDATE operation. By default, the first TIMESTAMP column in a
table is automatically set to the date and time of the most recent
operation if you do not assign it a value yourself. You can also set
any TIMESTAMP column to the current date and time by assigning it a
NULL value. Variations on automatic initialization and update
properties are described in [timestamp-4-1].

A TIMESTAMP value is returned as a string in the format 'YYYY-MM-DD
HH:MM:SS' with a display width fixed at 19 characters. To obtain the
value as a number, you should add +0 to the timestamp column.

Note: The TIMESTAMP format that was used prior to MySQL 4.1 is not
supported in MySQL 5.0; see MySQL 3.23, 4.0, 4.1 Reference Manual for
information regarding the old format.
