使用PHP将MySQL表导出到CSV的未定义错误

Question

I am using this snippet I found from an old post to download a MySQL table to CSV. It downloads the CSV fine, but I always get an 'undefined' error in with no other details that displays in my browser window. The CSV file does not contain any data about the error mixed in with the text. Any help with what my error is would be much appreciated.

I have tried testing my SQL statement, and that works fine.

$result = mysql_query("SELECT * FROM employees");
if (!$result) die('Couldn\'t fetch records');
$num_fields = mysql_num_fields($result);
$headers = array();
for ($i = 0; $i < $num_fields; $i++) {
    $headers[] = mysql_field_name($result , $i);
}
$fp = fopen('php://output', 'w');
if ($fp && $result) {
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename="employeelist.csv"');
    header('Pragma: no-cache');
    header('Expires: 0');
    fputcsv($fp, $headers);
    while ($row = mysql_fetch_assoc($result)) {
        fputcsv($fp, array_values($row));
    }
    die();
}

Answer 1

Sorry for the initial question, but I guess it was unrelated to my code somewhat. I think I found my problem.

The page was being linked from JQuery mobile, and even though it as a standard HTML page. Because of the page transitions with JQuery mobile, I think that is causing the message. Sorry for not considering that. I did not consider that as a pertinent detail. Thanks for all your suggestions.

Answer 2

Try changing your 'die' condition to this:

if (!$result) die( echo mysql_error() );

That will at least provide you with a little information to go on. You probably have more to troubleshoot after that, but you gotta start somewhere, and that's the beginning.

Step 2 for troubleshooting: use print_r( $headers ) right after the first for loop

Step 3 for troubleshooting: start printing debugging output within the while loop if neither of the first steps reveal anything useful. For example, use something like print_r( array_values( $row ) ) inside of that loop.

My original post should have more clearly stated that it was the first step in troubleshooting because you haven't provided any information about what you have done in your attempts to troubleshoot other than run the code.