Re: date_trunct() and start of week

On Thursday 26 November 2009 1:59:05 pm Thomas Kellerer wrote:
> Hi,
>
> while using date_trunc('week', some_date) to get the date of the first day
> of the week I noticed that it was working as expected: Monday is considered
> the start of the week.
>
> I assume this depends on some locale setting, but I can't figure out which
> it is, so I can make sure this is not "accidently" changed. I tried
> changing LC_TIME (American_America) but that still returned Monday as the
> first day (my understanding is that in the States Sunday is considered the
> start of the week)
>
> Any pointers are appreciated (did I miss it in the manual?)
>
> Regards
> Thomas

From here:
http://www.postgresql.org/docs/8.4/interactive/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC

week

The number of the week of the year that the day is in. By definition (ISO
8601), the first week of a year contains January 4 of that year. (The ISO-8601
week starts on Monday.) In other words, the first Thursday of a year is in week
1 of that year.

--
Adrian Klaver
aklaver(at)comcast(dot)net