Re: Interval "1 month" is equals to interval "30 days" - WHY?

...and even worse:

SELECT ('1 year'::interval) = ('360 days'::interval); --> TRUE :-)
SELECT ('1 year'::interval) = ('365 days'::interval); --> FALSE :-)

On Tue, Aug 7, 2012 at 4:42 PM, Dmitry Koterov <dmitry(at)koterov(dot)ru> wrote:

> Hello.
>
> I've just discovered a very strange thing:
>
> SELECT '1 mon'::interval = '30 days'::interval --> TRUE???
>
> This returns TRUE (also affected when I create an unique index using an
> interval column). Why?
>
> I know that Postgres stores monthes, days and seconds in interval values
> separately. So how to make "=" to compare intervals "part-by-part" and not
> treat "1 mon" as "30 days"?
>
> P.S.
> Reproduced at least in 8.4 and 9.1.
>