- var_dump: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
var_dump(date('Y-m-d', strtotime('00-00-00 00:00:00')));
var_dump(date('Y-m-d', strtotime('2000-00-00 00:00:00')));
var_dump(date('Y-m-d', strtotime('1999-12-00 00:00:00')));
var_dump(date('Y-m-d', strtotime('1999-11-30-00 00:00:00')));