Re: Scalar in a range (but textual not numeric)

On Wednesday 25 February 2004 22:37, Tom Lane wrote:
> I wrote:
> > try writing
> >     WHERE 'ABCDE' >= pr_min AND 'ABCDE' <= pr_max
> >           AND pr_min < (SELECT pr_min FROM table
> >                 WHERE pr_min > 'ABCDE'
> >                 ORDER BY pr_min LIMIT 1)
> > The idea here is to add an upper bound on pr_min to the index scan
> > conditions, so that the scan can stop short of the end of the index.
>
> Argh, got that backwards.  What you are missing is a *lower* bound on
> pr_min, and the index scan will therefore run from the start of the
> index up to pr_min = 'ABCDE'.  So reverse the sense of the added test:
>
>           AND pr_min >= (SELECT pr_min FROM table
>                  WHERE pr_min <= 'ABCDE'
>                  ORDER BY pr_min DESC LIMIT 1)

Aha! I was trying something like that, but couldn't get it quite right and it 
was getting too late for me to see clearly.

Thanks Tom, I'll have a play with this later today.
--  Richard Huxton Archonet Ltd