Validating the date in MySQL should be done using preg_match since ereg_* functions will be removed in PHP 6.

More info on PHP 6 changes: http://wiki.php.net/todo/php60 It appears there will be a module that you can use to utilize existing ereg expressions, so that’ll buy some time to port code from ereg* to preg*.
function isValidDate($date){

if (preg_match (“/^([0-9]{4})-([0-9]{2})-([0-9]{2})$/”, $date))
{

return true;
}
else{
return false;
}

}