use Goodby\CSV\Export\Standard\Exporter;
use Goodby\CSV\Export\Standard\ExporterConfig;
use Goodby\CSV\Export\Standard\CsvFileObject;
use Goodby\CSV\Export\Standard\Collection\PdoCollection;
use Goodby\CSV\Export\Standard\Collection\CallbackCollection;

require_once("vendor/autoload.php");

//DBの設定(postgreSQLの場合)
$pdo = new PDO('pgsql:host=localhost;dbname=hoge', 'postgres', '');

$stmt = $pdo->prepare("SELECT * FROM users");
$stmt->execute();

$collection = new CallbackCollection(new PdoCollection($stmt), function($row) {
    //ここにデータの処理など
    $row['name'] = strtoupper($row['name']);

    return $row;
});

//configの設定 SJISで出力する
$config = new ExporterConfig();
$config->setToCharset('SJIS-win');

//エクスポート
$exporter = new Exporter($config);
$exporter->export('users_converted.csv', $collection);