If I then have a rather large table (2 mio+ records) where is often do
a select with the where claus:

where
(((MyField1*100)+MyField2))>SomeValue

would I then gain something by either:

1.
Making a compined index on those two fields alone ?
Like this:

create index MyIdx
on MyTable (MyField1,MyField2);


2.
Make a new field in the table which is just a calculated fields
((MyField1*100)+MyField2) and then make an index on this new field ?


Michael

--- In ib-support@yahoogroups.com, "Martijn Tonies" <m.tonies@u...> wrote:
> Hi,
>
> > Can I make a index on two fields in a table, where the condition is
> > something like this:
> >
> > create index MyIdx
> > on MyTable (((MyField1*100)+MyField2));
>
> No.
>
>
> With regards,
>
> Martijn Tonies
> Database Workbench - the developer tool for InterBase & Firebird
> Upscene Productions
> http://www.upscene.com
>
> See you at the First European Firebird Conference in May in Fulda,
Germany
> http://www.firebird-conference.com