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$res = $modx->db->select('*', $table_name);
$rowcount = $modx->db->getRecordCount($res);

if($rowcount > 0) {

	header("Content-type: application/csv");
	header("Content-Disposition: attachment; filename=brochure-request-$d.csv");
	header("Pragma: no-cache");
	header("Expires: 0");

	while($row = $modx->db->getRow($res)) {
		
		if($c == 0) {
			$head = array_keys($row);
			$out .= implode(',', $head) . "\n";
		}
		
		$vals = array_values($row);
		$out .= implode(',', $vals) . "\n"; 
	
		$c++;
	}

<?php
$stmt = $modx->query("SELECT * FROM {$table_name}");
if ($stmt) {
	header("Content-type: application/csv");
	header("Content-Disposition: attachment; filename=brochure-request-$d.csv");
	header("Pragma: no-cache");
	header("Expires: 0");
	$c = 0;
	while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
		if($c == 0) {
			$head = array_keys($row);
			$out .= implode(',', $head) . "\n";
		}
		
		$vals = array_values($row);
		$out .= implode(',', $vals) . "\n"; 
	
		$c++;
    }
}