Quartile (etc) ranking in a SQL statement?

Here's a puzzler:

Given a query that returns rows ranked by some criteria, how can I write
another query around it that will give me the (say) first quartile (top
25%)? Another way of putting it is: if I have rows that look like this:

aaa | 1251
aba | 1197
cax | 1042
... | ...
axq | 23
(142 rows)

How can I write a query that will return these as

1 | aaa | 1251
2 | aba | 1197
3 | cax | 1042
... | ... | ...
142 | axq | 23

--
Jeff Boes vox 616.226.9550 ext 24
Database Engineer fax 616.349.9076
Nexcerpt, Inc. http://www.nexcerpt.com
...Nexcerpt... Extend your Expertise

In a PLPGPSQL script, once you know count(*) try

execute ''select * from table limit '' || int4( theCount / 4);

If you want numbering, create a sequence and add nextval() to the query.

JLL

Jeff Boes wrote:
>
> Here's a puzzler:
>
> Given a query that returns rows ranked by some criteria, how can I write
> another query around it that will give me the (say) first quartile (top
> 25%)? Another way of putting it is: if I have rows that look like this:
>
> aaa | 1251
> aba | 1197
> cax | 1042
> ... | ...
> axq | 23
> (142 rows)
>
> How can I write a query that will return these as
>
> 1 | aaa | 1251
> 2 | aba | 1197
> 3 | cax | 1042
> ... | ... | ...
> 142 | axq | 23
>
> --
> Jeff Boes vox 616.226.9550 ext 24
> Database Engineer fax 616.349.9076
> Nexcerpt, Inc. http://www.nexcerpt.com
> ...Nexcerpt... Extend your Expertise
>
> ---------------------------(end of broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an appropriate
> subscribe-nomail command to majordomo(at)postgresql(dot)org so that your
> message can get through to the mailing list cleanly