Return count between timestamps - Mailing list pgsql-novice

From Jonathan Davies
Subject Return count between timestamps
Date
Msg-id 20060313165110.2B8D25AF0BB@svr4.postgresql.org
Whole thread Raw
Responses Re: Return count between timestamps  (Andreas Kretschmer <akretschmer@spamfence.net>)
List pgsql-novice

Hi

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

Jonathan


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