Re: how to use aggregate functions in this case

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От David Johnston
Тема Re: how to use aggregate functions in this case
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Msg-id 1377628026127-5768721.post@n5.nabble.com
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Ответ на Re: how to use aggregate functions in this case  (David Johnston <polobo@yahoo.com>)
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David Johnston wrote
>
> Janek Sendrowski wrote
>> Hi,
>>
>>  
>>
>> thanks for all your answers.
>>
>> I'll have a try with the contains operator and the intrange, but
>> before I'd like to know if this would work:
>>
>>  
>>
>> CASE WHEN a >= 0 AND a < 25
>>
>> CASE WHEN a >= 25 AND a < 50
>>
>>  
>>
>> There wouldn't be a double endpoint. I just have to decide which
>> range the endpoint includes.
>>
>>  
>>
>> Janek Sendrowski
> Yes, using explicit comparison operators with "AND" will work just fine;
> its just a little more verbose so the other options, if available, are
> preferred from a readability standpoint.  I do not know whether the
> different options may have different performance characteristics.
>
> David J.

And just for completeness:

WITH range_def (low, high, label) AS (
VALUES (0, 25, '0 to 25'::varchar), (25, 50, '25 to 50')
)
SELECT ...
FROM source_data
JOIN range_def ON (val >= low AND val < high)
[the rest of the query]

David J.





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