framework/db/Query.php
public function all($db = null)
    {
        if ($this->emulateExecution) {
            return [];
        }
        $rows = $this->createCommand($db)->queryAll();
        return $this->populate($rows);
    }
public function all($db = null)
    {
        if ($this->emulateExecution) {
            return [];
        }
        $rows = $this->createCommand($db)->queryAll();
        return $this->populate($rows);
    }
Executes the query and returns all results as an array.
@param Connection $db the database connection used to generate the SQL statement.
If this parameter is not given, the `db` application component will be used.
@return array the query results. If the query results in nothing, an empty array will be returned.