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

[Adriano d. S. F. <adr...@uo...>]

Milan Babuskov wrote:
> Hi Claudio,
>
> Claudio Valderrama C. wrote:
>   
>> Since SQL allows to order by a field that doesn't appear in the SELECT list
>> (and I can't remember any restriction due to DISTINCT, do you see one in the
>> docs?)
>>     
>
> Suppose you have a table:
>
> X   Y
> --- ---
>    1   3
>    1   5
>    2   4
>
> What should the following query return: SELECT DISTINCT X ORDER BY Y?
>
> 1
> 2
>
> or
>
> 2
> 1
>   
DISTINCT act like an aggregate (MS Access has a FIRST aggregate 
function) causing many rows to become one.

So I think is not wrong to reject this query, like it's rejected when 
aggregate functions are used.


Adriano