다양한 프로그래밍 접근 방식(PHP 및 MySQL)에서 생년월일을 기준으로 사용자 연령을 계산하는 방법은 무엇입니까?

<code class="php">// Instantiate a DateTime object for the birth date
$birthDate = new DateTime('1999-03-15');

// Instantiate a DateTime object for the current date
$currentDate = new DateTime('now');

// Calculate the difference between the two dates in years
$age = $currentDate->diff($birthDate)->y;

// Output the age
echo $age;</code>

<code class="php">// Calculate the difference between the dates using date_diff()
$age = date_diff(date_create('1999-03-15'), date_create('now'))->y;

// Output the age
echo $age;</code>

<code class="sql">SELECT TIMESTAMPDIFF(YEAR, '1999-03-15', CURDATE()) AS age;</code>