Oscar Rodriguez Fonseca schrieb:
> TABLE IN DB:
>
>
> number_times | user_name | last_login
> ----------------------------------------
> 1 | Paul | 11-12-2005
> 4 | Mary | 08-11-2005
> 5 | Charles | 01-02-2005
>
> [...]
>
> SELECT count(*) AS number_times,NULL AS user_name,NULL as last_login \
> FROM table UNION ALL SELECT * FROM table LIMIT 2;
>
> This has the practical drawback that you need an integer column in your
> table to get the query working as expected and the design drawback that
> it is a little bit weird and somewhat non-standard way of querying.
>
I think this is a little bit to weired. It should be possible for
another person what I am doing without explaing such a lot.

> BTW, I had a similar problem and solved it storing the full result list
> in a temporal variable on the server but "session-wise" (when the user
> opens another unrelated page, the application frees the variable). This
> is possible in my case because my app won't have more than 10 clients
> at once and therefore it don't represent much memory overhead
This is possible if there are only little users and only a few hundred
records. I have only few users, too, but some tenthousonds records and I
don't think it would be a good idea storing them completly in the
servers memory.

Regards,
Verena

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Hi,

Sean Davis schrieb:
> It should still work just fine, again with the caveat that it is an
> approximation and depends on the statistics available. Try comparing the
> output a few times for your count(*) and using EXPLAIN.
>
sometimes the difference is to much to go this way. EXPLAIN extimates
71000 rows but there are 95000. 10% would have been accaptle. I did
these tests on a freshly vacuumed database.

regards,
Verena

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On 5/18/06 12:28 PM, "Verena Ruff" <lists@triosolutions.at> wrote:

> Hi,
>
> Sean Davis schrieb:
>> It should still work just fine, again with the caveat that it is an
>> approximation and depends on the statistics available. Try comparing the
>> output a few times for your count(*) and using EXPLAIN.
>>
> sometimes the difference is to much to go this way. EXPLAIN extimates
> 71000 rows but there are 95000. 10% would have been accaptle. I did
> these tests on a freshly vacuumed database.

You can change the statistics that are collected, if you like. Again, there
is stuff in the docs about doing that.

Sean


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Hi,

Sean Davis schrieb:
> You can change the statistics that are collected, if you like. Again, there
> is stuff in the docs about doing that
>
I didn't know that. Thanks for this hint, I'll read about it.

Regards,
Verena

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