最简单的方法是使用一个专门的CSV类，像这样:

$csv = new csv();
$csv->load_data(array(
    array('name'=>'John', 'age'=>35),
    array('name'=>'Adrian', 'age'=>23), 
    array('name'=>'William', 'age'=>57) 
));
$csv->send_file('age.csv'); 

要让它以CSV格式发送，并给出文件名，请使用header():

http://us2.php.net/header

header('Content-type: text/csv');
header('Content-disposition: attachment; filename="myfile.csv"');

至于创建CSV本身，您只需要遍历结果集，格式化输出并发送它，就像处理任何其他内容一样。

除了上述内容，你可能还需要补充:

header("Content-Transfer-Encoding: UTF-8");

它在处理包含多种语言的文件时非常有用，比如人名或城市。

下面是一个使用PDO并包含列标题的完整工作示例:

$query = $pdo->prepare('SELECT * FROM test WHERE id=?');
$query->execute(array($id));    
$results = $query->fetchAll(PDO::FETCH_ASSOC);
download_csv_results($results, 'test.csv'); 
exit();


function download_csv_results($results, $name)
{            
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename='. $name);
    header('Pragma: no-cache');
    header("Expires: 0");

    $outstream = fopen("php://output", "wb");    
    fputcsv($outstream, array_keys($results[0]));

    foreach($results as $result)
    {
        fputcsv($outstream, $result);
    }

    fclose($outstream);
}

Try:

header("Content-type: text/csv");
header("Content-Disposition: attachment; filename=file.csv");
header("Pragma: no-cache");
header("Expires: 0");

echo "record1,record2,record3\n";
die;

etc

编辑:这是我用来可选地编码CSV字段的代码片段:

function maybeEncodeCSVField($string) {
    if(strpos($string, ',') !== false || strpos($string, '"') !== false || strpos($string, "\n") !== false) {
        $string = '"' . str_replace('"', '""', $string) . '"';
    }
    return $string;
}

最简单的方法是使用一个专门的CSV类，像这样:

$csv = new csv();
$csv->load_data(array(
    array('name'=>'John', 'age'=>35),
    array('name'=>'Adrian', 'age'=>23), 
    array('name'=>'William', 'age'=>57) 
));
$csv->send_file('age.csv');