Quote Originally Posted by slimdave
Ah hah ... what you want is the predicate:
Code:
where b Is Null
the opposite of which is
Code:
where b Is Not null
I know you know the answer, but just to be painfully obvious I created a small demonstration of the
difference between NULL and 'NULL'. Parden my overzealousness.

Code:
  1  SELECT '|' || ASCII(NULL) || '| != ' ||
  2                ASCII('N')  || ' + '   ||
  3                ASCII('U')  || ' + '   ||
  4                ASCII('L')  || ' + '   ||
  5                ASCII('L') "NULL != 'NULL'"
  6*   FROM dual
SQL> /

NULL != 'NULL'
-----------------------
|| != 78 + 85 + 76 + 76