Re: [Firebird-devel] Firebird feature requests

[Eyal <ey...@re...>]

Dmitry Yemanov wrote:

> "Alex Kotov" <al_...@ya...> wrote:
> 
>>1) Better support of aliases in queries
>>For example the following query produces error but perfectly legal
>>from my point of view:
>>   select employeeid, sum( amount ) as income from payouts
>>    group by employeeid having income > 10000;
> 
> I understand such a wish, although I wound't assign it a high priority. We
> don't support CSE (common subexpression elimination), so now aliases just
> hide the fact that any complex aliased expression may be evaluated more than
> once. This is often a subject of hidden performance issues. Personally, I
> prefer explicitness in this case. More to type but much easier to understand
> what should be expected from the query.

 From the Release Notes of FB2alpha:

"Improved GROUP BY and ORDER BY clauses      A. Brinkman

Column aliases are now allowed in both these clauses.

Examples: ..."

Does this mean that column aliases are only supported for non-expression 
columns? Or that they are supported for GROUP/ORDER BY but not for HAVING?

Thanks,

Eyal.