Re: if !NULL ?

Is there a way to do to define a default value when doing this?

something like...

select distinct
        uid ....stuff...

      e.thingy  AS  Ifnull(ulk,description,'UNKNOWN'),

        ... more stuff ...

As I want to do is have a default value of "UNKNOWN" instead of null.



-----Original Message-----
From: Stephan Szabo [mailto:sszabo@megazone23.bigpanda.com]
Sent: Thursday, May 16, 2002 6:17 PM
To: Lev Lvovsky
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] if !NULL ?


On Thu, 16 May 2002, Lev Lvovsky wrote:

>
> ok, so more odd-ball questions
>
> I have two columns in a table:
>
> bool_bill | billing_id
>
> one is a boolean that determines if we bill a customer, and the other one
> is NULL if we don't, and has a billing_id of that customer if we do.  the
> billing_id uses a foreign key on the billing table to check that the
> billing_id exists.
>
> what I'd like to do is if bool_bill = y, then there has to be something in
> billing_id (automatically checked with the foreign key).
>
> again, do I need a function for this?

I think a table check constraint like:
(bool_bill=false or billing_id is not null)
will make billing_id not accept nulls when bool_bill is true.



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