首先将data作为String，以逗号作为分隔符(用“，”分隔)。就像这样

$CSV_string="No,Date,Email,Sender Name,Sender Email \n"; //making string, So "\n" is used for newLine

$rand = rand(1,50); //Make a random int number between 1 to 50.
$file ="export/export".$rand.".csv"; //For avoiding cache in the client and on the server 
                                     //side it is recommended that the file name be different.

file_put_contents($file,$CSV_string);

/* Or try this code if $CSV_string is an array
    fh =fopen($file, 'w');
    fputcsv($fh , $CSV_string , ","  , "\n" ); // "," is delimiter // "\n" is new line.
    fclose($fh);
*/

<?
    // Connect to database
    $result = mysql_query("select id
    from tablename
    where shid=3");
    list($DBshid) = mysql_fetch_row($result);

    /***********************************
    Write date to CSV file
    ***********************************/

    $_file = 'show.csv';
    $_fp = @fopen( $_file, 'wb' );

    $result = mysql_query("select name,compname,job_title,email_add,phone,url from UserTables where id=3");

    while (list( $Username, $Useremail_add, $Userphone, $Userurl) = mysql_fetch_row($result))
    {
        $_csv_data = $Username.','.$Useremail_add.','.$Userphone.','.$Userurl . "\n";
        @fwrite( $_fp, $_csv_data);
    }
    @fclose( $_fp );
?>

您可以使用fputcsv函数简单地将数据写入CSV。让我们看看下面的例子。将列表数组写入CSV文件

$list[] = array("Cars", "Planes", "Ships");
$list[] = array("Car's2", "Planes2", "Ships2");
//define headers for CSV 
header('Content-Type: text/csv; charset=utf-8');
header('Content-Disposition: attachment; filename=file_name.csv');
//write data into CSV
$fp = fopen('php://output', 'wb');
//convert data to UTF-8 
fprintf($fp, chr(0xEF).chr(0xBB).chr(0xBF));
foreach ($list as $line) {
    fputcsv($fp, $line);
}
fclose($fp);

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;
}

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@Andrew发布的php.net函数的改进版本。

function download_csv_results($results, $name = NULL)
{
    if( ! $name)
    {
        $name = md5(uniqid() . microtime(TRUE) . mt_rand()). '.csv';
    }

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

    $outstream = fopen("php://output", "wb");

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

    fclose($outstream);
}

它真的很容易使用，并且与MySQL(i)/PDO结果集一起工作。

download_csv_results($results, 'your_name_here.csv');

如果完成了页面，请记住在调用此函数后退出()。