get user by id

get-user-by-id.php

<?php
function getUserById($userId) {
    $sql = "SELECT users.*, 
                COALESCE((SELECT locations.friendlyAddress
                          FROM locations
                          WHERE locations.userId = users.id
                          ORDER BY locations.dateGather
                          DESC LIMIT 1), 'Unavailable') lastKnownLocation,
                COALESCE((SELECT CONCAT(locations.latitude, ',', locations.longitude)
                          FROM locations
                          WHERE locations.userId = users.id
                          ORDER BY locations.dateGather
                          DESC LIMIT 1), '') position
            FROM users
            WHERE users.id = $userId";
    return query($sql);
}