Re: inverse of "day of year"
От | Dana Hudes |
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Тема | Re: inverse of "day of year" |
Дата | |
Msg-id | Pine.LNX.4.58.0403221053390.12040@screamer.tcp-ip.info обсуждение исходный текст |
Ответ на | Re: inverse of "day of year" (Bruno Wolff III <bruno@wolff.to>) |
Ответы |
Re: inverse of "day of year"
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Список | pgsql-sql |
If you have the option to handle the date manipulation in Perl use the DateTime modules. Also see Date::Calc. A considerable amount of effort has been expended dealing with all the nitty-gritty of time manipulation. Use those modules , get your new date or time interval and feed that to the dbms with a straightforward inequality . Don't try to do date arithmetic in sql if you can avoid it you'll run afoul of something or other. On Mon, 22 Mar 2004, Bruno Wolff III wrote: > On Mon, Mar 22, 2004 at 10:14:40 -0300, > Martin Marques <martin@bugs.unl.edu.ar> wrote: > > > > Any thoughts on how this could affect date manipulation? > > This is consistant with what I explained about the behavior when adding > a month results in a day in a month past the end of the new month. > What do you expect to have happen here? > > > mydb=> select '29/2/2004'::date + ((2005 - date_part('year', now())::int) || > > 'years')::interval; > > ?column? > > --------------------- > > 2005-02-28 00:00:00 > > > > AFAIKS with other dates this works OK. :-) > > The real issue with intervals is that how they work in unusual cases is > not documented. The behavior could change in a future version without > much fanfare. > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) >
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