Re: Problem -Postgre sql

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От Chris Travers
Тема Re: Problem -Postgre sql
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Msg-id 4355E199.2040904@travelamericas.com
обсуждение исходный текст
Ответ на Re: Problem -Postgre sql  (Michael Glaesemann <grzm@myrealbox.com>)
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Correct me if I am wrong, but isn't COALESCE standard in this way?

Best Wishes,
Chris Travers
Metatron Technology Consulting

Michael Glaesemann wrote:

> [Please do not email me directly. Please post to the list so others  
> may help and benefit from the discussion.]
>
> On Oct 19, 2005, at 14:30 , Vikas J wrote:
>
>> IsNull in sql server has syntax like isnull(column,substitute)
>> if "column" is null it shows value of "substitute". That can be  
>> achieved
>> with CASE clause in postrgre but I want alternate function.
>
>
> If you look at the doc links I provided below, you will find that  
> COALESCE does exactly this.
>
>> Can you tell me how to write function like MAX() that will work  
>> directly  on
>> colmuns. I want to create my own function that will not need table  
>> name as
>> paramter.
>> it shld work similarly to max() function in postgre.
>
>
> [Again, it's PostgreSQL or Postgres. It is *not* spelled "postgre".]
>
> In my experience, the max() aggregate function does not require table  
> names as parameters and work on columns directly.
> http://www.postgresql.org/docs/8.0/interactive/functions-aggregate.html
>
> I suggest you take some time to look at the docs. They're quite  
> extensive and helpful.
> http://www.postgresql.org/docs/8.0/interactive/index.html
>
>
> Michael Glaesemann
> grzm myrealbox com
>
>
>>> I'm not quite sure what the ISNULL() function does in SQL Server, but
>>> it sounds like it might be similar to either COALESCE or the IS NULL
>>> expression.
>>>
>>> These pages might help you:
>>>
>>> COALESCE
>>> http://www.postgresql.org/docs/8.0/interactive/functions-
>>> conditional.html#AEN12056
>>>
>>> IS NULL
>>> http://www.postgresql.org/docs/8.0/interactive/functions- 
>>> comparison.html
>>
>
>
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