Date: Thu, 27 May 2010 12:43:36 +0200
From: "A. Kretschmer" <andreas.kretschmer@schollglas.com>
To: pgsql-sql@postgresql.org
Subject: Re: Check set of date intervals
Message-ID: <20100527104336.GD6907@a-kretschmer.de>
References: <AANLkTil8uYMMxel-SmWLDEuHPu0l2DHM0CjetnxAX3GL@mail.gmail.com>
	<20100527102713.GC6907@a-kretschmer.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20100527102713.GC6907@a-kretschmer.de>
User-Agent: Mutt/1.5.9i

In response to A. Kretschmer :
> > please, suggest an idea how to implement this in SQL without writing a
> > procedure.
> 
> There are a really nice additional contrib module from Jeff Davis,
> described here:
> 
> http://thoughts.j-davis.com/2010/03/09/temporal-postgresql-roadmap/
> 

short example, with your data:

test=# select * from rel_a;
 id | start_date |  end_date  |                         p
----+------------+------------+----------------------------------------------------
  1 | 01.01.2010 | 01.02.2010 | [01.01.2010 00:00:00 CET, 01.02.2010 00:00:00 CET)
  2 | 03.02.2010 | 04.03.2010 | [03.02.2010 00:00:00 CET, 04.03.2010 00:00:00 CET)
(2 rows)

test=# select * from rel_a where contains(p, period('15.01.2010'::date, '15.02.2010'::date));
 id | start_date | end_date | p
----+------------+----------+---
(0 rows)

test=# select * from rel_a where contains(p, period('15.01.2010'::date, '25.01.2010'::date));
 id | start_date |  end_date  |                         p
----+------------+------------+----------------------------------------------------
  1 | 01.01.2010 | 01.02.2010 | [01.01.2010 00:00:00 CET, 01.02.2010 00:00:00 CET)
(1 row)


The column p is created with:

test=# alter table rel_a add column p period;

and

test=# update rel_a set p = period(start_date, end_date);


Andreas
-- 
Andreas Kretschmer
Kontakt:  Heynitz: 035242/47150,   D1: 0160/7141639 (mehr: -> Header)
GnuPG: 0x31720C99, 1006 CCB4 A326 1D42 6431  2EB0 389D 1DC2 3172 0C99