Re: left outer join on more than 2 tables?

On 16/06/2009 19:12, Rob Sargent wrote the following:
> Richard Broersma wrote:
>> On Tue, Jun 16, 2009 at 2:40 PM, Rob Sargent<robjsargent@gmail.com> 
>> wrote:
>>
>>  
>>> Is there a city without a reference to region?
>>>     
>>
>> I don't know, but the OP wanted to know complaints by region.
>>
>>   
> I didn't try this, but with regionless cities, you may need a full join
> if you want a complete accounting of all complaints, some being logged
> to the null region.
> 
> 
>>
>>
>>  
>>>  And wouldn't you want to count(cm.id)?
>>>     
>>
>> Count(cm.id) and Count(*) produce the same result.  But I like
>> Count(*) more since it helps to correctly express the idea that we are
>> counting rows per group and not cm.id(s) per group.
>>
>>
>>
>>   
> 
> "Same result" is not true.  I loaded tables.
> Using count(*) you get count=1 for regions without complaints.  Using 
> count(complaint.id) you get count = 0.  (The deference amount to 
> counting the left hand side (region) vs the right hand side (complaint) 
> which I believe is what OP is after).
> 

Thanks everyone for your help. Your solutions worked. Much appreciated.
- Carol