Re: Setting week starting day

On Fri, Mar 09, 2007 at 20:13:11 -0300,
Jorge Godoy <jgodoy(at)gmail(dot)com> wrote:
> Bruno Wolff III <bruno(at)wolff(dot)to> writes:
>
> > No, it has to be inside the function so that the modular arithmetic is
> > applied to it.
>
> Then there's the error I've shown from your command. Can you give me a
> working one? This was with PostgreSQL 8.2.3.

postgres=# select date_trunc('week', current_date + 1);
date_trunc
------------------------
2007-03-05 00:00:00-06
(1 row)

It turns out DOW isn't available for date_trunc. You can probably use
extract to get what you want. You probably should check that it works
at DST transitions, since the date value is cast to a timestamp and
if DST transitions happen at 0000 in your time zone, you might get an
unexpected answer.

postgres=# select extract(dow from current_date + 1);
date_part
-----------
6
(1 row)