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 students in descending order of percentage of marks?

A - select first_name, last name, percentage_of_marks from students order by percentage_of_marks;

B - select first_name, last name, percentage_of_marks order by percentage_of_marks desc from students;

C - select first_name, last name, percentage_of_marks from students order by percentage_of_marks desc;

D - select first_name, last name, percentage_of_marks from students order by percentage_of_marks descending;

Q 2 - 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 correctly display the students’ first name, last name, honours subject and date of birth, born between July 1^st 1996, and 30^th June 1999.

A - select first_name, last name, honours_subject, date_of_birth from students where date_of_birth between ’30-JUN-1999’ and ’01-JUL-1996’;

B - select first_name, last name, honours_subject, date_of_birth from students where date_of_birth in (’30-JUN-1999’ , ’01-JUL-1996’);

C - select first_name, last name, honours_subject, date_of_birth from students where date_of_birth like ’30-JUN-1999’ and ’01-JUL-1996’;

D - select first_name, last name, honours_subject, date_of_birth from students where date_of_birth between ’01-JUL-1996’ and ’30-JUN-1999’;

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 true about the MAX and MIN functions?

A - Both can be used for any data type.

B - MAX returns the maximum value.

C - MIN returns the minimum value.

D - All are true.

Q 5 - You want to calculate the sum of commissions earned by the employees of an organisation. If an employee doesn’t receive any commission, it should be calculated as zero. Which will be the right query to achieve this?

A - select sum(nvl(commission, 0)) from employees;

B - select sum(commission, 0) from employees;

C - select nvl(sum(commission), 0) from employees;

D - None of the above.

Q 6 - Which of the following is true about inserting news rows to a table?

A - You must list values in the default order of the columns in the table.

B - You can also list the columns in the INSERT clause.

C - You can use the INSERT statement to add rows from one table to another.

D - All of the above.

Q 7 - Consider the following schema −

LOCATIONS(subject_code, department_name, location_id, city);

Which code snippet will alter the table LOCATIONS and add a column named Address, with datatype VARCHAR2(100)?

A - ALTER TABLE locations ADD (address varchar2(100));

B - ALTER TABLE locations ADD COLUMN(address varchar2(100));

C - MODIFY TABLE locations ADD COLUMN (address varchar2(100));

D - None of the above.

Q 8 - Which of the following is not true about complex views?

A - They derive data from more than one table.

B - They contain no functions or grouping.

C - You cannot perform DML operations through a complex view.

D - All of the above are true.

Q 9 - Which of the following is true about database indexes?

A - You can create an index on one or more columns.

B - Indexes always slow down the speed of query process.

C - Indexes are always created automatically.

D - Indexes should ideally be created on small tables.

Q 10 - Which of the following code would create a role named student_admin?

A - CREATE student_admin;

B - GRANT student_admin;

C - CREATE ROLE student_admin;

D - ROLE student_admin;