Re: if !NULL ?

Try the COALESCE function

dev=> select version();
version
-------------------------------------------------------------
PostgreSQL 7.2.1 on i686-pc-linux-gnu, compiled by GCC 2.96
(1 row)

dev=> SELECT COALESCE(NULL,'UNKNOWN');
case
---------
UNKNOWN
(1 row)

dev=> SELECT COALESCE('Temp','UNKNOWN');
case
------
Temp
(1 row)

Darren Ferguson

On Fri, 17 May 2002, McCaffity, Ray (Contractor) wrote:

> 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(at)megazone23(dot)bigpanda(dot)com]
> Sent: Thursday, May 16, 2002 6:17 PM
> To: Lev Lvovsky
> Cc: pgsql-general(at)postgresql(dot)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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