Re: [Firebird-devel] Using DISTINCT and ORDER BY together and

[Dmitry Y. <fir...@ya...>]

Arno Brinkman wrote:
>  
> If i understand correctly we currently allow unpredictable behaviour 
> when DISTINCT and ORDER BY are present and where ORDER BY include other 
> fields as in the select list.

After thinking more, I have to admit that I'd like us to reject such 
statements. As Arno has correctly pointed out, this is exactly the same 
issue as for GROUP BY vs ORDER BY and we disallow it since v1.5. While 
the visible effect is similar to the ordering by a hidden column, the 
situation is in fact different, because even the engine doesn't know how 
to produce a correct result.


Dmitry