From: Dan Nelson
Date: September 17 2002 7:30pm
Subject: Re: aggregate functions producing bad data
List-Archive: http://lists.mysql.com/mysql/119854
Message-Id: <20020917193037.GA17027@dan.emsphone.com>
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In the last episode (Sep 17), Brian Reichert said:
> On Tue, Sep 17, 2002 at 11:59:42AM -0700, Richard Unger wrote:
> > My query:
> > 
> > SELECT 
> > 	count(id), 
> > 	count( IF(call_end - call_start > 5, id, NULL) ), 
> > 	count( IF(call_end - call_start <= 5, id, NULL) )
> > FROM 
> > 	t_calllog_calls;
> > 
> > My result:
> > 
> > 1994
> > 1956
> > 35
> > 
> > However, 1956 + 35 != 1994.
> > 
> > Running MySQL 3.23.49-nt
> 
> One thing I'd check:  what happens if t_calllog_calls.id is NULL?

Also check if call_end or call_start are NULL; that will cause both IFs
to fail.  Don't you love NULLs :)
 
-- 
	Dan Nelson
	dnelson@stripped