To answer this question, let's analyze the given SQL statement:
SELECT LAST_NAME, SALARY, DEPARTMENT_ID
FROM EMP
WHERE DEPARMENT_ID = NULL;
The SQL statement is attempting to display the employees who have not been assigned to any department. However, the statement contains an error in the WHERE clause.
The correct operator to compare a column to a NULL value is the "IS NULL" operator, not the "=" operator.
Therefore, the correct answer is:
C. The operator in the WHERE clause should be changed to display the desired results