如何从mysqli结果中获得最低值？

$conn = new mysqli($servername, $username, $password, $dbname);
$query = "SELECT column_name FROM table_name";
$result = $conn->query($query);

$data = array();
while ($row = $result->fetch_assoc()) {
    $data[] = $row['column_name'];
}

$minValue = min($data);

$conn = new mysqli($servername, $username, $password, $dbname);
$query = "SELECT column_name FROM table_name";
$result = $conn->query($query);

$data = array();
while ($row = $result->fetch_assoc()) {
    $data[] = $row['column_name'];
}

$minValue = min($data);

echo "最小值为：" . $minValue;