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.