How does works "group by" correct

[Halldor Gislason]

Hi Carsten,
Here is a good refernce with examples:

http://www.1keydata.com/sql/sqlgroupby.html

best regards,
Halldor

On Aug 16, 2004, at 10:38 AM, SoftIl wrote:

> Hallo Halldor,
> thanks for your answer.
> Now I understand where my mistake was.
> I didn't know that I can use goup by only with an aggregate function.
> Now it is clear, why it could not work.
>
> Thanks
> Carsten
>
>
> ----- Original Message -----
> From: "Halldor Gislason" <halldorg at vortex.is>
> To: "Valentina Developers" <valentina at lists.macserve.net>
> Sent: Thursday, August 12, 2004 11:49 PM
> Subject: Re: How does works "group by" correct
>
>
>> "select *" returns all the fields so a group by does not really have a
>> purpose there.
>>
>> the purpose of the group by is to group the results of some aggregate
>> function by some fields so a group by without such a function has
>> little point
>>
>> you may instead be looking for the UNIQUE statement that will not
>> return records with duplicate values of of the field values you 
>> specify
>> as unique - I do not know how well Valentina supports UNIQUE
>>
>> to group by more than one field simply do:
>>
>> select a,b, count(*) from c group by a,b
>>
>> or
>>
>> select a,b, sum(c) from d group by a,b
>>
>> h
>>
>>
>>
>> On Aug 12, 2004, at 9:34 PM, SoftIl wrote:
>>
>>> Hi all,
>>> I've got some problems with "group by":
>>>
>>> 1)
>>> If I try this:
>>> select * from myTable group by date
>>> the "group by" statement hasn't an effect.
>>>
>>> If I write this
>>> select *,count(any column) from myTable group by date
>>> it works correct.
>>>
>>> Why is it so? In no documentation I could find this, that I have to 
>>> use
>>> "count()" if I'd like to use "group by".
>>>
>>> 2)
>>> How can I use "group by" for more than one column?
>>> This statement works not correct. I get all records return:
>>> select *,count(any column) from myTable group by date,ohrnummer
>>>
>>> Thanks for your help.
>>> Carsten
>>>
>>>
>>> _______________________________________________
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>>> Valentina at lists.macserve.net
>>> http://lists.macserve.net/mailman/listinfo/valentina
>>>
>>
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>
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