SQL Online Quiz

Q 1 - Consider the following schema −

STUDENTS(student_code, first_name, last_name, email, 
         phone_no, date_of_birth, honours_subject, percentage_of_marks);

Which of the following query would display names of all the students whose email ids are not provided?

A - select first_name, last name from students where email = 0;

B - select first_name, last name from students where email = ‘ ‘;

C - select first_name, last name from students where email is null;

D - select first_name, last name from students where email = ‘null’;

Q 2 - What is returned by TRUNC(789.8389, 2)?

A - 789.84

B - 789.83

C - 78

D - 789.00

Q 3 - Which of the following is true about Cartesian Products?

A - A Cartesian product is formed when a join condition is omitted.

B - A Cartesian product is formed when a join condition is valid.

C - Some rows in the first table are joined to all rows in the second table.

D - All rows in the first table are joined to some rows in the second table.

Q 4 - Which of the following is not a group function?

A - SUM

B - NVL

C - COUNT

D - MIN

Q 5 - Consider the following schema −

STUDENTS(student_code, first_name, last_name, email, 
         phone_no, date_of_birth, honours_subject, percentage_of_marks);

Which of the following query will correctly list the average percentage of marks in each honours subject, when the average is more than 50 percent?

A - select honours_subject, avg(percentage_of_marks) from students where avg(percentage_of_marks) > 50.0 group by honours_subject;

B - select honours_subject, avg(percentage_of_marks) from students having avg(percentage_of_marks) > 50.0 group by honours_subject;

C - select honours_subject, avg(percentage_of_marks) from students group by honours_subject having avg(percentage_of_marks) > 50.0;

D - None of the above.

Q 6 - Which of the following comparison operators could be used in a multiple row query?

A - IN operator

B - ANY operator

C - ALL operator

D - All of the above

Q 7 - Which of the following is NOT true about the SQL transaction control statements?

A - The COMMIT statement ends the current transaction and makes all data changes permanent.

B - The ROLLBACK statement ends the transaction and discards all the pending data changes.

C - Each DML statement is automatically committed.

D - All are true.

Q 8 - Which of the following is not true about a FOREIGN KEY constraint?

A - It is a referential integrity constraint.

B - It establishes a relationship between a primary key or a unique key in the same table or a different table.

C - A foreign key value cannot be null.

D - A foreign key value must match an existing value in the parent table.

Q 9 - Which of the following code will delete a view named all_marks_english?

A - delete view all_marks_english;

B - drop view all_marks_english;

C - delete all_marks_english;

D - drop all_marks_english;

Q 10 - Which of the following code would grant the role student_admin to a user named william?

A - grant student_admin to william;

B - grant to william student_admin;

C - grant william student_admin;

D - None of the above.