tgnwest

SELECT city.name city_name, COUNT(user.id) users FROM city LEFT JOIN user ON city.id = user.city_id GROUP BY city.name HAVING users >= M ORDER BY users DESC, city_name ASC LIMIT N

<button id="sendRequest">Отправить запрос</button>
$( function() {
$('#sendRequest').click( function() {
    $.get("url");
});
});