From: | Alban Hertroys <alban(at)magproductions(dot)nl> |
---|---|
To: | Michael Glaesemann <grzm(at)seespotcode(dot)net> |
Cc: | Karsten Hilbert <Karsten(dot)Hilbert(at)gmx(dot)net>, pgsql-general <pgsql-general(at)postgresql(dot)org> |
Subject: | Re: Why *exactly* is date_trunc() not immutable ? |
Date: | 2007-02-19 09:16:12 |
Message-ID: | 45D96ADC.50907@magproductions.nl |
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Lists: | pgsql-general |
Michael Glaesemann wrote:
>
> On Feb 19, 2007, at 18:04 , Alban Hertroys wrote:
>
>> Michael Glaesemann wrote:
>>>
>>> On Feb 18, 2007, at 20:29 , Karsten Hilbert wrote:
>>>
>>>> What I don't understand, however, is exactly *why* date_trunc is not
>>>> immutable ?
>>>
>>> I believe it's because the result of date_trunc depends on the time zone
>>> setting for the session.
>>
>> I understand the reasoning, but _under the conditions_ it is being used
>> by the OP it could have been immutable, right?
>
> *Under the conditions* doesn't really make sense wrt immutable
> functions. Immutable means is immutable under all conditions.
What I'm trying to say is not that it _is_ immutable, but that it
_behaves_ immutable (under said conditions).
This could imply that if a certain condition is available in a query on
which such a function operates, it would behave immutable.
--
Alban Hertroys
alban(at)magproductions(dot)nl
magproductions b.v.
T: ++31(0)534346874
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// Integrate Your World //
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