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: | 20060313165110.2B8D25AF0BB@svr4.postgresql.org |
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Lists: | 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
- - - - - - - - - - - - - - - - - -
Nixon.
+44 (0)1736 758600
White's Warehouse
Foundry Square
Hayle
Cornwall
TR27 4HH UK
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