- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
$value = '2010-10-21 54:254';
//$pattern = '(\d{4}(-\d{2})?(-\d{2})?( \d{2})?(:\d{2})?(:\d{2})?)';
$pattern = '(\d{4}-\d{2}-\d{2} \d{2}:\d{2}(:\d{2})?)';
var_dump(preg_match($pattern, $value));