private function combineSelectQuery($sqlParts)
    {
        // Add select columns and tables.
        $output = "SELECT " . $sqlParts['select'] . " FROM " . $sqlParts['from'];

        // Add where when defined.
        if ($sqlParts['where'] !== null) {
            // Add where
            $output .= " WHERE " . $sqlParts['where'];
        }

        // TODO: Add other parts.


        return $output;
    }