https://github.com/FounderDating/founderdating/blob/staging/members/application/libraries/repositories/user.php
    public function getReminderUsersByFilters($filters, $count = true){
....

        $query = ORM::factory('user')
                ->select('users.id, users.name, users.email')
                ->where('deleted IS', NULL)
                ->where('paused IS', NULL)
                ->orderby('users.id')
                ->groupby('users.id');
....
        if(!$this->isEmpty($paidArray)){
            $query->join('user_subscriptions', 'user_subscriptions.application_id', 'applications.id', 'LEFT');
            if($withWithout){
                $comparator = " = ";
                $connector = " OR ";
            }else{
                $connector = " AND ";
                $comparator = " != ";
            }
            $paidString = "";
            foreach($paidArray as $idx => $paid){
                if($idx != 0){
                    $paidString .= $connector;
                }
                switch($paid){
                    case "Yes - trial";
                    $paidString .= '`user_subscriptions`.`sub_type` '.$comparator.' "0"';
                    break;
                    case "Yes - paid";
                    $paidString .= '(`user_subscriptions`.`sub_status` '.$comparator.' 1 '.$connector.' `user_subscriptions`.sub_type '.$comparator.' 3)';
                    break;
                    case "No";
                        if($withWithout){
                            $paidString .= '(`user_subscriptions`.`sub_status` IS NULL '.$connector.' sub_status '.$comparator.' 0)';
                        }else{
                            $paidString .= '`user_subscriptions`.`sub_status` = 1';
                        }
                    break;
                }
            }
            $query->where("(".$paidString.")");
        }
....
            return $query->find_all();
....
    }