You might also want to look at the SQL command
CLUSTER, which physically reorders the table rows
based upon an existing index.
Andrew Gould
--- Ian Barwick <SUNGLASSESbarwick@gmx.net> wrote:
> Mike S. Nowostawsky wrote:
>
> > How can one select only a certain number of
> records in Postgres?
> >
> > In other SQL langs we can use, say, for the first
> 20 recs:
> >
> > select * from tablename where rownum < 21;
> >
> > WHAT should 'rownum' be to make this select
> work... OR is there a diff
> > syntax?
>
> use the LIMIT clause, e.g.
>
> SELECT * FROM tablename LIMIT 20
>
> for the first 20 rows, or
>
> SELECT * FROM tablename LIMIT 10,20
>
> for 10 rows beginning from the 20th row (or possibly
> the other way round,
> the caffeine isn't working yet ;-)
>
> When using LIMIT it is generally advisable to also
> use ORDER BY in order to
> guarantee consistent result sets over repeated
> queries.
>
> HTH
>
> Ian Barwick
>
>
> --
> Ian Barwick - Developer
> http://www.akademie.de
>
> Remove SUNGLASSES to reply ;-)
>
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