How did Vanka reach Moscow?

Mr. janak is using a table with following columns: Name, Class, Course _Id , Course_name. He needs to display names of students who have not been assigned any stream or have been assigned course_name that ends with “economics”.

He wrote the following command, which did not give the desired result.

SELECT Name, Class FROM Students WHERE Course_Name = Null OR Course_name=” %economics”;

Help Mr. janak to run the query by removing the error and write the correct query