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Return count between timestamps

From: "Jonathan Davies" <jonathan(at)nixondesign(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: Return count between timestamps
Date: 2006-03-13 16:51:07
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-novice

I have a car parking reservation table that stores 2 timestamps - entry_date
and exit_date.

There is a maximum number of car parking places, and I want to check that on
each day between the 2 requested reservation dates, the count of the
existing records does not exceed the maximum.

So I need some 'elegant' system of getting a count of all the existing
bookings for each of the days between the entry date and the exit date.

Unfortunately I have no idea how to GROUP by the dates between..

SELECT COUNT(id) as num_places FROM reservations r WHERE (('$entry_date' >
r.entry_date) AND ('$entry_date' < r.exit_date)) OR (('$exit_date' >
r.entry_date) AND ('$exit_date' < r.exit_date));

This obviously only returns the sum total - is there anyway I get this on a
day by day basis?

Many thanks


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Next:From: Richard KutDate: 2006-03-13 18:39:11
Subject: Exception in thread "main" java.lang.OutOfMemoryError
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Subject: Re: Automatic date/time

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