Re: [Firebird-devel] Firebird feature requests

[Dmitry Y. <di...@us...>]

"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.

> 2) Indexes should be used for unstrict search conditions
>
>     For example index is _used_ during execution of query below:
>     select recid from mytable where status = 0;
>
>     but NOT used during execution of the following query
>     (even if valid plan was specified);
>     select recid from mytable where status < 1;

I'm pretty sure the index _is_ used. Feel free to prove me wrong with a real
example.


Dmitry