Export Mysql Table to CSV Using PHP - What's Wrong?

I liked this example because it was intuitive and matched my needs: http://www.a2zwebhelp.com/export-data-to-csv

Problem is, it's using mysql as opposed to mysqli so here's what I've got:

set_time_limit(600);
include ("carter.inc");
$cxn = mysqli_connect($host,$user,$password,$database)
or die ("couldn't connect to server");

$output="";

$michelle="select * from verizon_test order by id";
$michelle_query=mysqli_query($cxn, $michelle)
or die("Michelle didn't work");
$michelle_columns=mysqli_field_count($cxn);

//gets the field names from your table and sets them up as the first row in your csv file

for($i=0; $i<$michelle_columns; $i++)
{
$heading=mysqli_fetch_fields($michelle_query);
$output	.='"'.$heading.'",';
}
$output.="\n";

/*
while($michelle_row=mysqli_fetch_array($michelle_query))
{
	for($i=0; $i<$michelle_columns; $i++)
	{
		$output .='"'.$michelle_row["$i"].'",';
	}
$output.="\n";
}

$filename="json.csv";
header('Content-type:appliation/csv');
header('Content-Dispoition: attachment; filename='.$filename);

echo $output;
exit;*/

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There's more than one problem here, but the first thing I want to tackle is my column names.

The example I liked is using a deprecated function, but I can't figure out how to get mysqli_fetch_fields working. I know it's supposed to be an array, but every time I try to write it as $heading=mysqli_fetch_fields($michelle_query, $i), I get "Warning: mysqli_fetch_fields() expects exactly 1 parameter, 2 given in C:\wamp\www\json\csv_test.php on line 19"

Where am I blowing it?