Обсуждение: Fractional Results

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Fractional Results

От
pocm@rnl.ist.utl.pt (Paulo J. Matos)
Дата:
Hi all,

I'm doing a sql query to get an average of some tables. SQL has
an average command but unfortunately we cannot use it since out
information is not in only one column, we've done the following:
select temp1.espl / temp2.iluminados 
from (select count(*) as espl from esp) as temp1,     (select count(distinct id) as iluminados from esp) as temp2;

After some testing i found out that temp1.espl / temp2.iluminados 
gives us always the floor of the real value. I would like the
fractional number instead of the floor. 
Any ideas on this topic?

Best regards,
-- 
Paulo J. Matos : pocm(_at_)rnl.ist.utl.pt
Instituto Superior Tecnico - Lisbon    
Software & Computer Engineering - A.I.- > http://www.rnl.ist.utl.pt/~pocm ---    Yes, God had a deadline...    So, He
wroteit all in Lisp!
 



Re: Fractional Results

От
Tom Lane
Дата:
pocm@rnl.ist.utl.pt (Paulo J. Matos) writes:
> After some testing i found out that temp1.espl / temp2.iluminados 
> gives us always the floor of the real value.

If these are integers, try casting them to floats before dividing.
Integer division is generally understood to yield the floor().
        regards, tom lane