How to create and download a csv file from php script?

I don't have enough reputation to reply to @complex857 solution. It works great, but I had to add ; at the end of the Content-Disposition header. Without it the browser adds two dashes at the end of the filename (e.g. instead of "export.csv" the file gets saved as "export.csv--"). Probably it tries to sanitize \r\n at the end of the header line.

Correct line should look like this:

header('Content-Disposition: attachment;filename="'.$filename.'";');

In case when CSV has UTF-8 chars in it, you have to change the encoding to UTF-8 by changing the Content-Type line:

header('Content-Type: application/csv; charset=UTF-8');

Also, I find it more elegant to use rewind() instead of fseek():

rewind($f);

Thanks for your solution!

You can use the built in fputcsv() for your arrays to generate correct csv lines from your array, so you will have to loop over and collect the lines, like this:

$f = fopen("tmp.csv", "w");
foreach ($array as $line) {
    fputcsv($f, $line);
}

To make the browsers offer the "Save as" dialog, you will have to send HTTP headers like this (see more about this header in the rfc):

header('Content-Disposition: attachment; filename="filename.csv";');

Putting it all together:

function array_to_csv_download($array, $filename = "export.csv", $delimiter=";") {
    // open raw memory as file so no temp files needed, you might run out of memory though
    $f = fopen('php://memory', 'w'); 
    // loop over the input array
    foreach ($array as $line) { 
        // generate csv lines from the inner arrays
        fputcsv($f, $line, $delimiter); 
    }
    // reset the file pointer to the start of the file
    fseek($f, 0);
    // tell the browser it's going to be a csv file
    header('Content-Type: text/csv');
    // tell the browser we want to save it instead of displaying it
    header('Content-Disposition: attachment; filename="'.$filename.'";');
    // make php send the generated csv lines to the browser
    fpassthru($f);
}

And you can use it like this:

array_to_csv_download(array(
  array(1,2,3,4), // this array is going to be the first row
  array(1,2,3,4)), // this array is going to be the second row
  "numbers.csv"
);

Update:
Instead of the php://memory you can also use the php://output for the file descriptor and do away with the seeking and such:

function array_to_csv_download($array, $filename = "export.csv", $delimiter=";") {
    header('Content-Type: application/csv');
    header('Content-Disposition: attachment; filename="'.$filename.'";');

    // open the "output" stream
    // see http://www.php.net/manual/en/wrappers.php.php#refsect2-wrappers.php-unknown-unknown-unknown-descriptioq
    $f = fopen('php://output', 'w');

    foreach ($array as $line) {
        fputcsv($f, $line, $delimiter);
    }
}   

Try... csv download.

<?php 
mysql_connect('hostname', 'username', 'password');
mysql_select_db('dbname');
$qry = mysql_query("SELECT * FROM tablename");
$data = "";
while($row = mysql_fetch_array($qry)) {
  $data .= $row['field1'].",".$row['field2'].",".$row['field3'].",".$row['field4']."\n";
}

header('Content-Type: application/csv');
header('Content-Disposition: attachment; filename="filename.csv"');
echo $data; exit();
?>

That is the function that I used for my project, and it works as expected.

function array_csv_download( $array, $filename = "export.csv", $delimiter=";" )
{
    header( 'Content-Type: application/csv' );
    header( 'Content-Disposition: attachment; filename="' . $filename . '";' );

    // clean output buffer
    ob_end_clean();
    
    $handle = fopen( 'php://output', 'w' );

    // use keys as column titles
    fputcsv( $handle, array_keys( $array['0'] ), $delimiter );

    foreach ( $array as $value ) {
        fputcsv( $handle, $value, $delimiter );
    }

    fclose( $handle );

    // flush buffer
    ob_flush();
    
    // use exit to get rid of unexpected output afterward
    exit();
}