public static function allValues($valueKey, $query, $parameters = [], $errorHandler = null)
    {
        // execute query
        $result = static::query($query, $parameters, $errorHandler);

        $records = [];
        while ($record = $result->fetch(PDO::FETCH_ASSOC)) {
            $records[] = $record[$valueKey];
        }

        return $records;
    }