ISRO2018-42

Question

Consider the set of relations given below and the SQL query that follows:

Students: (Roll_number, Name, Date_of_birth)
Coursed: (Course_number, Course_name, Instructor)
Grades: (Roll_number, Course_number, Grade)

SELECT DISTINCT Name
FROM Students, Courses, Grades
WHERE Students.Roll_number = Grades.Roll_number
                            AND   Courses.Intructor =Sriram
                            AND   Courses.Course_number = Grades.Course_number
                            AND   Grades.Grade = A

Which of the following sets is computed by the above query?

1. Names of Students who have got an $\textsf{A}$ grade in all courses taught by Sriram
2. Names of Students who have got an $\textsf{A}$ grade in all courses
3. Names of Students who have got an $\textsf{A}$ grade in at least one of the courses taught by Sriram
4. None of the above 

Comments

https://gateoverflow.in/969/gate2003-86

Answer 1

course.intsructor = sriram specify the course taught by sriram and other two predicate specify that students can get A grade atleast.
so by these three predicate option C is correct.