PHP: Generate CSV from mysql and email out

<?php

//mysql user variables
$mysqli = new mysqli("localhost", "user", "password", "database");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

//grab all rows from the table where state is "new" and put into array 
$query = "SELECT Field1,Field2";

//loop the fetch and concactenate into string
if ($result = $mysqli->query($query)) {        

    $data[] = array('Field1','Field2');
    while ($row = $result->fetch_assoc()) {
        $data[] = array($row['Field1'],$row['Field2']);
 }
    $result->free();
}

function create_csv_string($data2) {
 // Open temp file pointer
 if (!$fp = fopen('php://temp', 'w+')) return FALSE;
 
 // Loop data and write to file pointer
 foreach ($data2 as $line) fputcsv($fp, $line);
 
 // Place stream pointer at beginning
 rewind($fp);
 
 // Return the data
 return stream_get_contents($fp);
}

function send_csv_mail ($csvData, $body, $to = 'to email address',  $from = 'senders email',$subject = 'Test email with attachment' ) {
 // This will provide plenty adequate entropy
 $multipartSep = '-----'.md5(time()).'-----';
 
 // Arrays are much more readable
 $headers = array("From: $from","Reply-To: $from","Content-Type: multipart/mixed; boundary=\"$multipartSep\"");
 
 // Make the attachment
 $attachment = chunk_split(base64_encode(create_csv_string($csvData))); 
 
 // Make the body of the message
 $body = "--$multipartSep\r\n"
        . "Content-Type: text/plain; charset=ISO-8859-1; format=flowed\r\n"
        . "Content-Transfer-Encoding: 7bit\r\n"
        . "\r\n"
        . "$body\r\n"
        . "--$multipartSep\r\n"
        . "Content-Type: text/csv\r\n"
        . "Content-Transfer-Encoding: base64\r\n"
        . "Content-Disposition: attachment; filename=\"AFILE.csv\"\r\n"
        . "\r\n"
        . "$attachment\r\n"
        . "--$multipartSep--";
 // Send the email, return the result
 return @mail($to, $subject, $body, implode("\r\n", $headers)); 
}

echo "emaling now <br>";
$resp=send_csv_mail($data, "Here is Today's Report:");
if( $resp ){
 echo "Mail sent <br>" ;
} else {
 echo "Mail not sent <br>";
}

echo "fin <br>";
?>