Hey Everyone, what am i doing wrong??, uggg

what i'm trying to do is fairly simple but is not working. (am using mysqli)
i'm selecting all fields from a single column called city code and then attempting to put into an array called $citiesArr. i know what line is not working but don't know how to what to do instead.

maybe i shouldn't be using fetch_fields()..?

PHP Code:
$citiesArr = array();

$getCitiesSql 'select city_code from locations_city';
$result $mysqli->query($getCitiesSql)) {
//echo 'res exists';
$getCities $result->fetch_fields();
$getCities as $val) { //ERROR IS HERE

big thanks in advance for any help on this