Comments on: The UNKNOWN null. Friends of Oracle and Java Sat, 25 Apr 2015 11:36:47 +0000 hourly 1 By: Patrick Sinke Tue, 29 Aug 2006 08:22:24 +0000 And that’s a thing I did not know… I always thought that ” != null. About time they change that…..

By: Laurent Schneider Mon, 28 Aug 2006 16:04:54 +0000 One I do hate about nulls is this one

select length(”) from dual;

of course one would expect to have 0 as the length of an empty string.

Still Oracle may change this in a very future release, as stated in

Oracle Database currently treats a character value with a length of zero as null. However, this may not continue to be true in future releases, and Oracle recommends that you do not treat empty strings the same as nulls.

it will be fun I promise !

By: Viliam Mon, 28 Aug 2006 15:32:36 +0000 It’s quite complicated even for some Oracle programmers, see this bug:

By: Chen Shapira Mon, 28 Aug 2006 08:39:11 +0000 Thats a terriffic summary! No matter how long you’ve been looking at databases, NULLs always remain a bit unexpected. I’ve bookmarked this article and will probably refer to it time and again when things get murky again :-)