How to perform a subquery with a QueryBuilder object?

Queries are only resolved until they're executed, you can add an events manager to your connection to check which SQL's are sent to the database server:

<?php

$di['db'] = function() use ($config) {

    $eventsManager = new Phalcon\Events\Manager();

    //Listen all the database events
    $eventsManager->attach('db', function($event, $connection) {
        if ($event->getType() == 'beforeQuery') {
             $sqlVariables = $connection->getSqlVariables();
             if (is_array($sqlVariables)) {
                echo $connection->getSqlStatement(), ' ', join(', ', $sqlVariables), '<br>';
             } else {
                echo $connection->getSqlStatement(), '<br>';
             }
        }
    });

    $connection = new \Phalcon\Db\Adapter\Pdo\Mysql(array(
        "host" => $config->database->host,
        "username" => $config->database->username,
        "password" => $config->database->password,
        "dbname" => $config->database->name
    ));

    $connection->setEventsManager($eventsManager);

    return $connection;
};

Nice! Thank you!

What about performing a subquery using the QueryBuilder? Is it possible or should I use raw sql?

Subqueries aren't still supported in PHQL, we need to update the PHQL's planner to translate the subqueries correctly. You can use a raw sql or write the subquery as a join,

Hello,

Do you know how can I do this query with join? PHQL doesn't support subqueries wich is a big pain so I have to find alternatnives. Raw sql I didn't understood how to use.

SELECT * FROM location WHERE id NOT IN (SELECT location_id FROM user_location WHERE user_id=1000);

I have two tables: one with locations and one with likes and dislikes from user to those locations. I want to retrive all the locations that the user didn't voted yet. I don't want to retrive locations that the user allready voted.

Thank you so much!