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From: jiiiiim@hotmail.com
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Subject: Re: All hail Bob (not)!
Date: 7 May 2006 20:42:00 -0700
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Xref: dp-news.maxwell.syr.edu comp.databases.theory:39294

Frank Hamersley wrote:
> Bob Badour wrote:

[..]

>> I agree it is no problem to write the query to get the average ages
>> where the age is known. Using null, how does one write the query to
>> get the correct result, ie. the average is unknown ?

> select case when count(*) = count(age)
>             then avg(age)
>             else null
>        end as avgage
> from   table

What say you Bob?  The silence to date has been most instructive.

Cheers, Frank.