Consider the relational database with the following four schemas and their…

Consider the relational database with the following four schemas and their respective instances.

    Student(sNo, sName, dNo) Dept(dNo, dName)

    Course(cNo, cName, dNo) Register(sNo, cNo)

SQL Query:

SELECT * FROM Student AS S WHERE NOT EXIST

     (SELECT cNo FROM Course WHERE dNo = “D01”

                 EXCEPT
     SELECT cNo FROM Register WHERE sNo = S.sNo) 

The number of rows returned by the above SQL query is___________.