The YEAR type is a 1-byte type used for representing years.
MySQL retrieves and displays YEAR values in YYYY format. The range is 1901 to 2155.
You can specify YEAR values in a variety of formats:
As a four-digit string in the range '1901' to '2155'.
As a four-digit number in the range 1901 to 2155.
As a two-digit string in the range '00' to '99'. Values in the ranges '00' to '69' and '70' to '99' are converted to YEAR values in the ranges 2000 to 2069 and 1970 to 1999.
As a two-digit number in the range 1 to 99. Values in the ranges 1 to 69 and 70 to 99 are converted to YEAR values in the ranges 2001 to 2069 and 1970 to 1999. Note that the range for two-digit numbers is slightly different from the range for two-digit strings, because you cannot specify zero directly as a number and have it be interpreted as 2000. You must specify it as a string '0' or '00' or it will be interpreted as 0000.
As the result of a function that returns a value that is acceptable in a YEAR context, such as NOW().
Illegal YEAR values are converted to 0000.