Re: converting a specified year and week into a date - Mailing list pgsql-general

From A. Kretschmer
Subject Re: converting a specified year and week into a date
Date
Msg-id 20070214081343.GE1303@a-kretschmer.de
Whole thread Raw
In response to Re: converting a specified year and week into a date  (Ron Johnson <ron.l.johnson@cox.net>)
Responses Re: converting a specified year and week into a date  (Ron Johnson <ron.l.johnson@cox.net>)
List pgsql-general
am  Wed, dem 14.02.2007, um  2:01:09 -0600 mailte Ron Johnson folgendes:
> >> i was just wondering if it was at all possible to turn a year and a given
> >> week number into a real date just using postgresql commands?
> >>
> >>
> >> e.g. if i have year = 2004 and week = 1,
> >>     can i turn that into say 2004-01-01 (so that the specified
> >>     date is the one for the beginning of week 1 in the year 2004
> >
> > You can extract the week from a given date with this:
> >
> > SELECT EXTRACT(WEEK FROM '2006-01-01'::date);
> >
> > Be careful, the 1.1. can be in the 52. week in the last year. If you
> > know the first day in the year in week 1, then you can add 7* the given
> > week-1 days to this date.
>
> I think she wants to do the opposite: cast 2004w1 to YYYY-MM-DD format.

I know, but to do this do you need to know the first day in this week...


Andreas
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Andreas Kretschmer
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