private function getColumnAlias($columnName, $mode, array $customRenameColumns)
    {
        switch ($mode) {
            case self::COLUMN_RENAMING_INCREMENT:
                return $columnName . $this->sqlCounter++;

            case self::COLUMN_RENAMING_CUSTOM:
                return isset($customRenameColumns[$columnName])
                    ? $customRenameColumns[$columnName] : $columnName;

            case self::COLUMN_RENAMING_NONE:
                return $columnName;

        }
    }