Re: Just comments about math

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On 2001 December 7 12:34 pm, Edipo Elder Fernandes de Melo wrote:

> =# select (3+0.2*707/80)*80;
> ?column?
> ----------
> 381.4
>
> =# SELECT 80*(3+(707/80)*0.2);
> ?column?
> ----------
> 368
>
> Answer: "select 707/80;" returns 8, while "select 707/80::float"
> returns 8.8375.

SELECT 707.0/80; --> 8.8375

In your first expression, you change type to floating point in your first
operation, but in your second expression you don't change type until the
second to last operation. Integer division always returns an integer result,
even when it's not the most mathematically intuitive way to do things.

- --
Andrew G. Hammond mailto:drew(at)xyzzy(dot)dhs(dot)org http://xyzzy.dhs.org/~drew/
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"To blow recursion you must first blow recur" -- me
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