Create CSV File From Remote MySQL using PHP - php

Question

I have adapted the info from this site but instead of creating a csv file, it is only displaying the info in the command screen it is being executed in. I have tried entering $fileName = 'C:\Users\dmcgettigan\Desktop\mysql-export.csv'; and just the filename but I do not have a file being generated. Thank you in advance for your help, I am trying to teach myself php, and mysql!
Updated: added code
My Code:
<?php
//Our MySQL connection details.
$host = 'mysql_server';
$user = 'user';
$password = 'password';
$database = 'database';
//Connect to MySQL using PDO.
$pdo = new PDO("mysql:host=$host;dbname=$database", $user, $password);
//Create our SQL query.
$sql = "SELECT
a.InvoiceNumber, a.partnumber, a.Quantity, b.Discount, date
FROM
data a,
mars b
WHERE
a.PartNumber = b.partnumber
AND date >= '2018-09-28'
AND mfg = 'gk'
AND discount <> '0.00'
AND CustomerNumber IN ('Z5447520' , 'Z3715177', 'Z1234444', 'Z5425966')
AND Quantity > '0'";
//Prepare our SQL query.
$statement = $pdo->prepare($sql);
//Executre our SQL query.
$statement->execute();
//Fetch all of the rows from our MySQL table.
$rows = $statement->fetchAll(PDO::FETCH_ASSOC);
//Get the column names.
$columnNames = array();
if(!empty($rows)){
//We only need to loop through the first row of our result
//in order to collate the column names.
$firstRow = $rows[0];
foreach($firstRow as $colName => $val){
$columnNames[] = $colName;
}
}
//Setup the filename that our CSV will have when it is downloaded.
$fileName = 'mysql-export.csv';
//Set the Content-Type and Content-Disposition headers to force the download.
header('Content-Type: application/excel');
header('Content-Disposition: attachment; filename="' . $fileName . '"');
//Open up a file pointer
$fp = fopen('php://output', 'w');
//Start off by writing the column names to the file.
fputcsv($fp, $columnNames);
//Then, loop through the rows and write them to the CSV file.
foreach ($rows as $row) {
fputcsv($fp, $row);
}
//Close the file pointer.
fclose($fp);

Answer 1

$fp = fopen('php://output', 'w'); this specific line should be changed to $fp = fopen($filename, 'w'); because as is you are using the output as the file