Re: Fastest way / best practice to calculate "next birthdays"

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Hannes Dorbath <light(at)theendofthetunnel(dot)de>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Fastest way / best practice to calculate "next birthdays"
Date: 2008-05-04 16:11:34
Message-ID: 481DE036.90706@commandprompt.com
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Hannes Dorbath wrote:
> The subject basically says it all, I'm looking for the fastest
> (indexable) way to calculate the next birthdays relative to NOW() from a
> dataset of about 1 million users.
>
> I'm currently using a function based index, but leap year handling /
> mapping February 29 to February 28 gives me some headaches.
>
> Is there any best practice to do that in PostgreSQL?

postgres=# SELECT current_date|| ' a ' || to_char(current_date, 'Day'),

current_date + '1 Year'::interval || ' a ' || to_char(current_date + '1
Year'::interval, 'Day') as next_birthday;
?column? | next_birthday
------------------------+---------------------------------
2008-05-04 a Sunday | 2009-05-04 00:00:00 a Monday

?

Sincerely,

Joshua D. Drake

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