### 11.2.8 2-Digit Years in Dates

 Date values with 2-digit years are ambiguous because the century is unknown. Such values must be interpreted into 4-digit form because MySQL stores years internally using 4 digits.

 For [`DATETIME`](datetime.html), [`DATE`](datetime.html), and [`TIMESTAMP`](datetime.html) types, MySQL interprets dates specified with ambiguous year values using these rules:

* Year values in the range `00-69` become `2000-2069`.

* Year values in the range `70-99` become `1970-1999`.

 For `YEAR`, the rules are the same, with this exception: A numeric `00` inserted into `YEAR` results in `0000` rather than `2000`. To specify zero for `YEAR` and have it be interpreted as `2000`, specify it as a string `'0'` or `'00'`.

 Remember that these rules are only heuristics that provide reasonable guesses as to what your data values mean. If the rules used by MySQL do not produce the values you require, you must provide unambiguous input containing 4-digit year values.

`ORDER BY` properly sorts [`YEAR`](year.html) values that have 2-digit years.

 Some functions like [`MIN()`](aggregate-functions.html#function_min) and [`MAX()`](aggregate-functions.html#function_max) convert a [`YEAR`](year.html) to a number. This means that a value with a 2-digit year does not work properly with these functions. The fix in this case is to convert the [`YEAR`](year.html) to 4-digit year format.

