$query = "SELECT * FROM clients";   

if (!$result = mysqli_query($con, $query)) {
    exit(mysqli_error($con));
}

$users = array();
if (mysqli_num_rows($result) > 0) {
    while ($row = mysqli_fetch_assoc($result)) {
        $users[] = $row;
    }
}

header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename=Users.csv');
$output = fopen('php://output', 'w');
fputcsv($output, array('name'));

if (count($users) > 0) {
    foreach ($users as $row) {
        fputcsv($output, $row);
    }
}

mysqli_close($con);

我得到的输出：

Lubbe,
Williams,
"van den Berg",
"van Straaten",
Schutte

预期产量：

Lubbe,
Williams,
van den Berg,
van Straaten,
Schutte