From: Louis-David Mitterrand <vindex+lists-pgsql-sql@apartia.org>
To: pgsql-sql@postgresql.org
Subject: UNION or LEFT JOIN?
Date: Tue, 16 Feb 2010 15:08:14 +0100
Message-ID: <20100216140814.GA22577@apartia.fr> (raw)
Here is the basic schema:
-------------------------->id_ship>-----------------------
| |
[SHIP]->id_ship->[CABIN]->id_cabin->[PRICE]<-id_cruise<-[CRUISE]
It's a database of cruise prices.
Each 'price' object has a reference to 'cabin' and 'cruise'
'cabin' belongs to a 'ship', so does 'cruise'
I'm trying to select all cabins of cruise N°1 with prices OR nothing if
there is no price (meaning cabin not available). I want all cabins
listed, price or no price.
Also when doing the query I don't have the id_ship, only the id_cruise.
What is the best way of doing it? UNION or LEFT JOIN? I tried the latter
without success and am unsure on how do do the former.
Thanks,
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To: pgsql-sql@postgresql.org
Cc: vindex+lists-pgsql-sql@apartia.org
Subject: Re: UNION or LEFT JOIN?
In-Reply-To: <20100216140814.GA22577@apartia.fr>
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