Re: Problem -Postgre sql

[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