Re: Auomatic numbering, replacing nulls and IF

> 1) Is it possible to create an INT PRIMARY KEY column that automagically
> numbers itself? MS-SQL does this using the IDENTITY keyword.

As you already mentioned, SERIAL/SEQUENCEs.

> 2) The ISNULL function in both Oracle and MS-SQL takes 2 numbers and
returns
> the second if the first is null, otherwise it returns the first. ISNULL in
> Postgres seems to be something quite different. Before I go writing my own
> function to do it, is there one already?

I think you're looking for coalesce():

"COALESCE(value[, ...])
The COALESCE function returns the first of its arguments that is not NULL.
This is often useful to substitute a default value for NULL values when data
is retrieved for display, for example:

SELECT COALESCE(description, short_description, '(none)') ...'

> 3) How do I do 'IF this_sql THEN that_sql'? I keep getting:
> parse error at or near "IF"

I'm not sure exactly what you need... but it sounds a lot like CASE:

http://postgresql.overtone.org/users-lounge/docs/7.2/postgres/functions-cond
itional.html

Greg