Re: NULLs

On Tue, 20 Dec 2005 21:33:34 +0000, Andrew Clark <lark047_at_hotmail.com> wrote:

>Hello,
>
>I have an application whose database was recently upgraded from 7 to 9i. In
>a bit of code, columns are compared that may both be null. In Oracle 7,
>will two columns compare equal if they are both NULL? In 9i it seems that
>they do not and I have to change it to NVL(column1) = NVL(column2).
>
>Thanks,
>Andrew

the sql language has three valued logic. An expression can result in true, false and null.
If you compare NULL to NULL the result is NULL, the test will fall through.
This has been the case in any version of Oracle.

--
Sybrand Bakker, Senior Oracle DBA