MySQL → Выборка людей определённого возраста

CREATE TABLE `users` (
    `id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    `name` VARCHAR(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '',
    `birthday` DATE NOT NULL 
) ENGINE = MYISAM

$yearOfBirth = 26;
$date1 = date((date('Y') - $yearOfBirth - 1) . '-m-d');
$date2 = date((date('Y') - $yearOfBirth) . '-m-d');
$sql = "
    SELECT * FROM `users`
    WHERE `birthday` BETWEEN '$date1' AND '$date2'
";

$yearOfBirth1 = 25;
$yearOfBirth2 = 27;
$date1 = date((date('Y') - $yearOfBirth2 - 1) . '-m-d');
$date2 = date((date('Y') - $yearOfBirth1) . '-m-d');
$sql = "
    SELECT * FROM `users`
    WHERE `birthday` BETWEEN '$date1' AND '$date2'
";