Re: strange result for select * from table where id=random()*900

[Kristo Kaiv <kristo(dot)kaiv(at)skype(dot)net>]

On 27.07.2007, at 10:48, Stefan Zweig wrote:

hi list,

this is my query:

select 

*

from _g2977 

where 

id=floor(random() * (900));

in table _g2977 i have id(s) from 1 up to 900. i just want to select one random dataset by the above query but i does not work.

actually i get sometime zero, sometimes one, sometimes two and sometimes even three results back from the above query although i thought it should give only one random dataset from the table.

what is wrong?

i appreciate any help.

thanks in advance, stefan

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SELECT * FROM _g2977 g,

(SELECT floor(random() * (900) as rnd) r

WHERE g.id = r.rnd

should work better, haven't tested though.

Kristo Kaiv

http://kaiv.wordpress.com (PostgreSQL blog)