Yeah, this is universal behavior, not specific to Oracle. In raw SQL
I usually use "nvl", but I guess until we support functions in
expressions, explicit null checking is required.
Andrus
On Aug 20, 2006, at 5:04 AM, Mike Kienenberger wrote:
Apparently, life gets worse. Oracle makes it very difficult to
compare outer join record values.
Nulls do not equal anything, nor do they "not equal" anything.
http://thinkoracle.blogspot.com/2005/06/nulls-in-oracle.html
So if I want to compare any column from a left outer join, I have to
explicitly handle the nulls somehow.
For example, use nvl to provide an alterate default value whenever a
null is found.
( (nvl(RTRIM(t4.IS_ACTIVE), 'N') <> 'Y')
Should something like this be automatically done for any outer join
implementation?
We can't use nvl genericly, but we can add another clause:
(x is null) or (x <> 'Y') for an inequality.
(x is not null) and (x = 'Y') for an equality
Apparently the behavior can vary from database to database and even
between join and search clauses for some databases. No end of fun.
