ORA-00908

Title :

ORA-00908 missing NULL keyword

Cause :
Either of the following: In a CREATE TABLE or ALTER TABLE statement, NOT was entered to specify that no null values are allowed in that column, but the keyword NULL was omitted. In the IS [NOT] NULL logical operator, the keyword NULL was not found. For example, the following statement generates this message: SELECT * FROM EMP WHERE DEPTNO IS NOT; The keyword NULL must follow the keywords IS NOT.

Action :
Correct the syntax.