Message-ID: <48293319.2000201@nsoft.lt>
Date: Tue, 13 May 2008 09:20:09 +0300
From: Julius Tuskenis <julius@nsoft.lt>
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CC: pgsql-admin@postgresql.org
Subject: Re: how to get a number of seconds in some interval ?
References: <482849B0.6050103@nsoft.lt>
	<200805121724.38772.achill@matrix.gatewaynet.com>
	<48285507.4010007@nsoft.lt>
	<200805121801.35101.achill@matrix.gatewaynet.com>
	<20080.1210604951@sss.pgh.pa.us>
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Thank you, it's now clear to me.

Tom Lane rašė:
> Achilleas Mantzios <achill@matrix.gatewaynet.com> writes:
>   
>> Στις Monday 12 May 2008 17:32:39 ο/η Julius Tuskenis έγραψε:
>>     
>>> do you know why division of intervals was not implemented? As I see it - 
>>> there should be an easy way to do so. '1 hour 30 minutes' / '1 hour' = 
>>> 1.5 .... Seems straight forward...
>>>
>>>       
>> No idea why. However as you pose it,it makes sense.
>>     
>
> No, it doesn't really, because intervals contain multiple components.
> What would you define as the result of
> 	'1 month 1 hour' / '1 day'
> bearing in mind that the number of days per month is not fixed, and
> neither is the number of hours per day?
>
> You can derive a number if you're willing to make arbitrary assumptions
> about the relationships of the different units (as indeed extract(epoch)
> does), but hard-wiring such assumptions into a basic arithmetic operator
> doesn't seem like a good idea to me.
>
> 			regards, tom lane
>
>   


-- 
Julius Tuskenis
Programavimo skyriaus vadovas
UAB nSoft
mob. +37068233050