Re: help with query: advanced ORDER BY...

On Sun, 15 Jan 2006 me@alternize.com wrote:

> > Something you may consider doing is creating a view that masks the
> > screen_number in those cases, something like
> >
> > create view schedule_public_view as
> > select theater_id
> > , screen_date
> > , screen_time
> > , case when no_screen_number then 0 else screen_number  end as
> > screen_number
> > , movie_name
> > from schedules;
>
> wouldn't this be the same problem: pgsql not using the index for
> screen_number anymore?

Theoretically an expressional index with the case expression should be
usable for sorting with more complicated expressions like that. That
really only an option if theres a small number of fixed orders though (and
in testing it looked like you might need to play with settings to get it
chosen).