Re: Advanced Query

From: Michael Fuhr <mike(at)fuhr(dot)org>
To: operationsengineer1(at)yahoo(dot)com
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: Advanced Query
Date: 2006-06-02 17:43:25
Message-ID: 20060602174325.GA2073@winnie.fuhr.org
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On Fri, Jun 02, 2006 at 10:09:01AM -0700, operationsengineer1(at)yahoo(dot)com wrote:
> Michael, my derivative of your query example works
> great - thank you!
>
> i think i understand everything except why multiplying
> by 1.0 is necessary. when i take it out, my expected
> result, 0.50000000000..., turns into 0 - so i assume
> it has to do with formatting the result.

Integer division yields integers, so 1 / 2 = 0 whereas 1.0 / 2.0 = 0.5.
The expression therefore needs something to force a non-integer result.
Multiplying by 1.0 (or 100.0) is one way; using 1.0 and 0.0 in the CASE
expression is another; casting one of the operands to numeric or one of
the floating-point types is yet another.

--
Michael Fuhr

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