Re: Why *exactly* is date_trunc() not immutable ?

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@magproductions.nl

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