YEAR[(4)]

A year in four-digit format. MySQL displays YEAR values in YYYY format,
but permits assignment of values to YEAR columns using either strings
or numbers. Values display as 1901 to 2155, and 0000.

*Note*:

The YEAR(2) data type is deprecated and support for it is removed in
MySQL 5.7.5. To convert YEAR(2) columns to YEAR(4), see
http://dev.mysql.com/doc/refman/5.7/en/migrating-to-year4.html.

For additional information about YEAR display format and interpretation
of input values, see http://dev.mysql.com/doc/refman/5.7/en/year.html.

URL: http://dev.mysql.com/doc/refman/5.7/en/date-and-time-type-overview.html

