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Re: JOIN vs. LEFT JOIN

From: "Nico Callewaert" <callewaert(dot)nico(at)telenet(dot)be>
To: "Andreas Wenk" <a(dot)wenk(at)netzmeister-st-pauli(dot)de>
Cc: <pgsql-novice(at)postgresql(dot)org>
Subject: Re: JOIN vs. LEFT JOIN
Date: 2009-01-28 12:49:35
Message-ID: 2292C8EBC4EB4A209BE6EBF2BE05F51A@etsinformatics.local (view raw or flat)
Thread:
Lists: pgsql-novice
> Ok please don't get me wrong for asking again: one customer can have two 
> tax rates? Why?
> Because he's living in the USA and has a taxrate of 25% and lives also in 
> Germany and has
> 19%? Hm ... strange ... ;-) . And also the custumer is 'prospect' OR 'not 
> active' ... but
> not both ... ;-)
>
>> drop downs in the application, so the customer can easily select a value.
>
> So all these dropdowns are multiselect ...?
>
> I am not sure if I can help you with this. My idea is really to think 
> about the design of
> the application and / or the database ... again - please don't get me 
> wrong ...


Hi Andreas,

I think we are not understanding each other :-)
It's al the time just 1 value, 1 value for tax, 1 value for customer type. 
No multiselect drop downs.  But all these fields are of course referencing a 
lookup table by ID.  But like Regina also said, the performance hit of the 
LEFT JOIN seems not worth considering putting junk data in the database that 
should be NULL (if the drop down is left blanc)...
I don't know if I made myself clear ?

Thanks !
Nico 



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Subject: Re: JOIN vs. LEFT JOIN
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