You could use a CASE statement...

select
        type,
        sum(sales),
        sum(cost),
      CASE WHEN sum(sales) <> 0 THEN (sum(sales) * sum(cost) / sum(sales)) *
100 ELSE 0 END
from test
group by 1

However, I guess that your example is just not what you really use as
sum(sales) * sum(cost) / sum(sales) seems very similar to sum(cost).....


----------------------------------------------------------------------------
--------------- 
Patrick Fiche 
email : [EMAIL PROTECTED] 
tél : 01 69 29 36 18 
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--------------- 




-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Tim Nelson
Sent: mercredi 19 octobre 2005 14:27
To: pgsql-general@postgresql.org
Subject: [GENERAL] getting around---division by zero on numeric 


I am getting division by zero on a calculated field ( sum(sales) is 0 ) 
and I can't find a way around this.  I figured out you can't use an 
aggregate in a where, and using having the parser must (obviously) 
evaluate the select fields before considering teh having clause.

Does anyone have a way around this?  Thanks!

select
        type,
        sum(sales),
        sum(cost),
        (sum(sales) * sum(cost) / sum(sales)) * 100
from test
group by 1
having sum(sales) != 0


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