php 根据出生日期生成年龄

<?php

$birthday = '1985-02-01';
$age = date('Y', time()) - date('Y', strtotime($birthday)) - 1;
if (date('m', time()) == date('m', strtotime($birthday))){

	if (date('d', time()) > date('d', strtotime($birthday))){
	$age++;
	}
}elseif (date('m', time()) > date('m', strtotime($birthday))){
	$age++;
}
echo $age;


?>


mysql 当前时间-n年计算
select date_add(curdate(), interval -1 year);