Re: [SQL] calculating percentages

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От Thomas Good
Тема Re: [SQL] calculating percentages
Дата
Msg-id Pine.LNX.3.96.990713090122.13446A-100000@admin.nrnet.org
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Ответ на Re: [SQL] calculating percentages  ("D'Arcy" "J.M." Cain <darcy@druid.net>)
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On Tue, 13 Jul 1999, D'Arcy J.M. Cain wrote:

> Thus spake Thomas Good
> > > > How does one do this:   SELECT (current_value/target) * 100;
> > The divison rtns 0, which multiplied by 100, rtns 0.
> 
> Does "SELECT (current_value * 100)/target" work better?

Darcy, 

SELECT (2 * 100)/3;             
       ?column?
----------------
66
(1 row)                              

This is clean and I don't have to truncate the value in the end.  
Thanks!  

BTW, I noticed an idiosnycratic behaviour that I don't really
care for when doing floating point calculations:

SELECT (2::float8/3::float8) * 100;
       ?column?
----------------
66.6666666666667    <----------------- I don't need to round up here.
(1 row)                              

EOF

So, Larry W comes in handy again:

#!/usr/bin/perl
$val = (2/3) * 100;
print("$val\n");

66.6666666666666    

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