You can use the NOT logical operator in combination with any SAS and WHERE expression operator. And you can combine the NOT operator with AND and OR. For example: where skill not eq 'cobol' or years ...

The prefix operator NOT is also a logical operator. The result of putting NOT in front of a quantity whose value is 0 (false) is 1 (true). That is, the result of negating a false statement is 1 (true) ...

Boolean logical operators in Excel formulas make searching easier, ... Example: =NOT(100>500) TRUE because 100 is NOT greater than 500. XOR – also called Exclusive OR, ...