$file = fopen('demosaved.csv', 'w');

// save the column headers
fputcsv($file, array('Column 1', 'Column 2', 'Column 3', 'Column 4', 'Column 5'));

// Sample data. This can be fetched from mysql too
$data = array(
array(01523, 'Data 12', 'Data 13', 'Data 14', 'Data 15')
);

// save each row of the data
foreach ($data as $row)
{
fputcsv($file, $row);
}

// Close the file
fclose($file);