Subject: null values in attributes

From: Sushil Da Silva <[email-masked]>
Date: Wed, 4 Mar 92 18:53:30 -0800

Hi,

We are trying to retrieve tuples from a class, selecting on a
attributed that is undefined or null. Here's the query:

-----------
Go
* retrieve (s.all) from s in student where placed_in = NULL
\g

Query sent to backend is "retrieve (s.all) from s in student where
placed_in = NULL "
Error: No response from the backend, exiting...
-----------

As you can see, the monitor hangs for a while and then exits without
delivering any results. Can anyone tell me what we're doing wrong?
We greatly appreciate any help.

Thanks
Sushil da Silva

---

From: postarch (Postgres Mailing Archive)
Date: Thu, 05 Mar 92 10:46:19 PST

> attributed that is undefined or null. Here's the query:

The problem is that postgres doesn't handle nulls very well.  NULL is
a reserved keyword in the language, so the parser accepts it, but the
backend doesn't know what to do with it and subsequently lays and egg.
Hopefully after 4.0 we can address this problem once and for all.

Jeff Meredith
[email-masked]