## Re: how to get a number of seconds in some interval ?

From: Achilleas Mantzios pgsql-admin(at)postgresql(dot)org Tom Lane , Julius Tuskenis Re: how to get a number of seconds in some interval ? 2008-05-13 06:56:50 200805130956.51872.achill@matrix.gatewaynet.com (view raw or whole thread) 2008-05-12 13:44:16 from Julius Tuskenis  2008-05-12 14:24:38 from Achilleas Mantzios   2008-05-12 15:01:34 from Achilleas Mantzios    2008-05-12 15:09:11 from Tom Lane     2008-05-13 06:20:09 from Julius Tuskenis     2008-05-13 06:56:50 from Achilleas Mantzios      2008-05-13 08:22:28 from "Scott Marlowe"       2008-05-13 08:41:00 from Achilleas Mantzios       2008-05-13 08:42:41 from Shane Ambler        2008-05-13 08:48:32 from "Scott Marlowe"      2008-05-13 14:15:27 from Tom Lane pgsql-admin
```Στις Monday 12 May 2008 18:09:11 ο/η Tom Lane έγραψε:
> Achilleas Mantzios <achill(at)matrix(dot)gatewaynet(dot)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?
>

SELECT extract(epoch from '1 month'::interval)/(60*60*24) as "Days in 1 month interval";
Days in 1 month interval
--------------------------
30
(1 row)
So it seems that the arbitary assumption of (1 month=30 days, and 1 day = 24 hours) has already been made
in the extract function.

> 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
>

--
Achilleas Mantzios

```

### Responses

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