From: Michael Glaesemann <grzm@myrealbox.com>
To: Vikas J <vikas.jadhav@codecindia.com>
Cc: postgresql sql list <pgsql-sql@postgresql.org>
Subject: Re: Problem -Postgre sql
Date: Wed, 19 Oct 2005 14:41:25 +0900
Message-ID: <8FB39706-1EFC-4D9F-ADBD-1311D4B08940@myrealbox.com> (raw)
In-Reply-To: <00b101c5d46e$3cd6fa60$6f0aa8c0@codecindia.com>
References: <000c01c5ce34$61797c20$6f0aa8c0@codecindia.com>
<E80C316D-C8FB-457A-8032-ABF6A4A36AB0@myrealbox.com>
<00b101c5d46e$3cd6fa60$6f0aa8c0@codecindia.com>
[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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Cc: grzm@myrealbox.com, vikas.jadhav@codecindia.com
Subject: Re: Problem -Postgre sql
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