Re: Comparisons in Relational Algebra

Thanks. I think your suggestion is right. Not any language but just plain relational algebra expression.

Philip Lijnzaad wrote:

> Tan> Let's say I want to select those tuples where the Year falls between
> Tan> 1990 and 1995. Is there a shorter way of expressing this?
>
> Tan> sigma Year >= 1990 ^ Year <= 1995 (relation)
>
> I don't know what language this is, but maybe ``sigma 1990 <= Year <= 1995''
> would be OK?
>
> In SQL, you would of course say
> SELECT ...
> FROM ...
> WHERE year BETWEEN 1990 AND 1995;
>
> Cheers,
> Philip
> --
> /dev/brain: character special (53/0)
> -----------------------------------------------------------------------------
> Philip Lijnzaad, lijnzaad_at_ebi.ac.uk \ European Bioinformatics Institute,rm A2-24
> +44 (0)1223 49 4639 / Wellcome Trust Genome Campus, Hinxton
> +44 (0)1223 49 4468 (fax) \ Cambridgeshire CB10 1SD, GREAT BRITAIN
> PGP fingerprint: E1 03 BF 80 94 61 B6 FC 50 3D 1F 64 40 75 FB 53

--
Regards,
Chee Sin