CLUSTER (was Re: get certain # of recs)

Note:

In postgresql, CLUSTER is severly broken. Don't use it if you value your
data.

...Maybe its time to yank cluster completely?

-alex
On Fri, 14 Sep 2001, Andrew Gould wrote:

> 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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