$str_accommodation_level = "SELECT * FROM interest";
$query_accommodation_level = $dbcon->query($str_accommodation_level);
while ($accommodation_level = $query_accommodation_level->fetch_array()) {
    $level_from = 'type' . $accommodation_level['id'];
    if (isset($_COOKIE[$level_from])) {
        $level_data += '<span>' . $_COOKIE[$level_from] . '</span> <br>';
    }
    print $level_data;
}

$arr = array('1','2','3','4');
$str=implode(",",$arr);

INSERT INTO table_name (column1)
VALUES ('$str')

@$filename= $_POST['filename'];
    $title = implode(',',@$filename);
    $sql .="INSERT INTO createtest_filename(id,filename) VALUES('".$max_id."','".$title."');";