correct order by in sql request

I tried to substitute ORDER BY ? ASC into ORDER BY ? DESC in the fetch request, only to discover that the current code was not correct. The only reason why this was not a visible bug is that Isso currently does not use this capability to order comments differently and the output order is the database order.

Explanations on what did not work: http://stackoverflow.com/questions/6995497/find-by-sql-and-single-quotes-in-an-order-by-clause

I decided to use a strong custom sanitization because we don't need anything more complicated here and that's the safer way.