Non-Repeating Digits

/* Write a PHP script NonRepeatingDigits.php that declares an integer variable N, and then finds
all 3-digit numbers that are less or equal than N (<= N) and consist of unique digits.
Print "no" if no such numbers exist. */

<?php
function printAllNumbersWith3UniqueDigits($maxNumber) {
    if ($maxNumber > 987) {
        $maxNumber = 987;
    }

    $uniqueNumbers = [];
    for ($i = 102; $i <= $maxNumber; $i++) {
        $last = $i % 10;
        $middle = (int)(($i / 10) % 10);
        $first = (int)(($i / 100) % 10);
        if ($first != $middle && $first != $last && $middle != $last) {
            $uniqueNumbers[] = $i;
        }
    }

    if (count($uniqueNumbers)) {
        echo '<p>' . implode(", ", $uniqueNumbers) . "</p>\n";
    } else {
        echo "<p>no</p>\n";
    }
}

printAllNumbersWith3UniqueDigits(1234);
printAllNumbersWith3UniqueDigits(145);
printAllNumbersWith3UniqueDigits(15);
printAllNumbersWith3UniqueDigits(247);
?>