--- not 

The `not' keyword is used as part of the `where' clause to
   negate an entire boolean expression.

The `not' condition can be represented by the word `not' or by 
   the `not equal' symbol (^=).

EXAMPLE:

	  sql> where dept_no = 60 and
		     job ^= 'engineer*'

	  sql> where not [job = 'salesman*' or salary >= 2000]
