Return 30% of results?

Nick wrote on 18.09.2009 23:31:

Is there a way to return a percentage of the rows found? I tried
window functions but get an error...

ERROR: syntax error at or near "OVER"

SELECT id, cume_dist FROM (
SELECT id, cume_dist() OVER (ORDER BY id) FROM employees
) s
WHERE cume_dist < 0.3

Works for me. Are you sure you are using Postgrs 8.4?
(Windowing functions are not available in earlier versions)

Regards
Thomas

//Display the top 40 % of rows in BB_DEPARTMENT

SQL> select ROWNUM,ID FROM EMPLOYEES WHERE ROWNUM < .3*(SELECT COUNT(ID) FROM BB
_DEPARTMENT) GROUP BY ROWNUM,ID;

ROWNUM
----------
1
HTH
Martin Gainty
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From: nboutelier@gmail.com
Subject: [GENERAL] Return 30% of results?
Date: Fri, 18 Sep 2009 14:31:29 -0700
To: pgsql-general@postgresql.org

Is there a way to return a percentage of the rows found? I tried
window functions but get an error...

ERROR: syntax error at or near "OVER"

SELECT id, cume_dist FROM (
SELECT id, cume_dist() OVER (ORDER BY id) FROM employees
) s
WHERE cume_dist < 0.3

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On Fri, Sep 18, 2009 at 07:54:30PM -0400, Martin Gainty wrote:

//Display the top 40 % of rows in BB_DEPARTMENT

SQL> select ROWNUM,ID FROM EMPLOYEES WHERE ROWNUM < .3*(SELECT COUNT(ID) FROM BB
_DEPARTMENT) GROUP BY ROWNUM,ID;

ROWNUM
----------
1
HTH
Martin Gainty

That's Oracle, not PostgreSQL. Are you really trying to help here?

Cheers,
David.
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com

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On Sep 18, 3:40 pm, spam_ea...@gmx.net (Thomas Kellerer) wrote:

Nick wrote on 18.09.2009 23:31:> Is there a way to return a percentage of the rows found? I tried

window functions but get an error...

ERROR:  syntax error at or near "OVER"

SELECT id, cume_dist FROM (
  SELECT id, cume_dist() OVER (ORDER BY id) FROM employees
) s
WHERE cume_dist < 0.3

Works for me. Are you sure you are using Postgrs 8.4?
(Windowing functions are not available in earlier versions)

Regards
Thomas

--
Sent via pgsql-general mailing list (pgsql-gene...@postgresql.org)
To make changes to your subscription:http://www.postgresql.org/mailpref/pgsql-general

Yeah, im actually not using 8.4. Any other alternatives?

On Sat, Sep 19, 2009 at 12:27:10AM -0700, nick wrote:

On Sep 18, 3:40�pm, spam_ea...@gmx.net (Thomas Kellerer) wrote:

Nick wrote on 18.09.2009 23:31:> Is there a way to return a percentage of the rows found? I tried

window functions but get an error...

ERROR: �syntax error at or near "OVER"

SELECT id, cume_dist FROM (
� SELECT id, cume_dist() OVER (ORDER BY id) FROM employees
) s
WHERE cume_dist < 0.3

Works for me. Are you sure you are using Postgrs 8.4?
(Windowing functions are not available in earlier versions)

Regards
Thomas

--
Sent via pgsql-general mailing list (pgsql-gene...@postgresql.org)
To make changes to your subscription:http://www.postgresql.org/mailpref/pgsql-general

Yeah, im actually not using 8.4. Any other alternatives?

The easiest way would be to upgrade to 8.4 because the workarounds for
previous versions are complicated and bug-prone.

Cheers,
David.
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate

On Sat, Sep 19, 2009 at 3:27 AM, nick <nboutelier@gmail.com> wrote:

On Sep 18, 3:40 pm, spam_ea...@gmx.net (Thomas Kellerer) wrote:

Nick wrote on 18.09.2009 23:31:> Is there a way to return a percentage of the rows found? I tried

window functions but get an error...

ERROR:  syntax error at or near "OVER"

SELECT id, cume_dist FROM (
  SELECT id, cume_dist() OVER (ORDER BY id) FROM employees
) s
WHERE cume_dist < 0.3

Works for me. Are you sure you are using Postgrs 8.4?
(Windowing functions are not available in earlier versions)

Using 8.3? You can use arrays to stack a set and then pull some records out:

create or replace function some_employees() returns setof employee as
$$
declare
employees_arr employees[];
n_found int;
n_returned int;
begin
select array
(
select employees from employees
where x order by y
) into employees_arr;

n_found := array_upper(employees_arr, 1);
n_returned := n_found * 0.3;
return query select (e).* from unnest(employees_arr[1:n_returned]) as e;
end;
$$ language plpgsql;

couple notes:
*) 8.3 has doesn't have unnest, but it can be made (google array_explode).
*) probably some typos in above...i didn't test it
*) needs some error checking
*) not scalable to huge numbers of records
*) 8.4 can do this much easier!

merlin