Generate and look at the query plan, then run the query and look at the
statistics.
It would be a clever optimiser that would have specific code to analyse
EXTRACT (YEAR FROM DT.DATA) <= 2016
and work out that it could use an index (rather than just saying "oh,
the stuff to the left of the <= is just a general expression, so I'll
have to calculate it for every record"), whereas
DT.DATA <= '12/31/2016'
needs no such cleverness. One might therefore reasonable expect that,
using *any* RDBMS, the first approach is rather more likely to end up as
a table scan.
But if you really want to know, generate and look at the query plan and
statistics, on a table with realistic data and production indexes.
On 09/12/2016 11:35, Luigi Siciliano [email protected]
[firebird-support] wrote:
> Hallo,
>
> what is more performant from subject?
>
> I would prepare myself for a table that grows rapidly.
>
> Is the same in FB 2.5.6 or 3.0.1?
>
> Thanks
--
Tim Ward
------------------------------------
------------------------------------
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Visit http://www.firebirdsql.org and click the Documentation item
on the main (top) menu. Try FAQ and other links from the left-side menu there.
Also search the knowledgebases at http://www.ibphoenix.com/resources/documents/
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
------------------------------------
Yahoo Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/firebird-support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/firebird-support/join
(Yahoo! ID required)
<*> To change settings via email:
[email protected]
[email protected]
<*> To unsubscribe from this group, send an email to:
[email protected]
<*> Your use of Yahoo Groups is subject to:
https://info.yahoo.com/legal/us/yahoo/utos/terms/
