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 - What is returned by MOD(1000,30)?

A - 33

B - 30

C - 3

D - 10

Q 3 - Which of the following is not true about USING clause?

A - When more than one column has the same name, USING clause is used for specifying the column to be joined by equijoin.

B - It is used for matching one column only.

C - You can use a table name or alias in the referenced columns.

D - The NATURAL JOIN and the USING clauses are mutually exclusive.

Q 4 - Which of the following is true about a group function?

A - Group functions operate on sets of rows to produce multiple results per group.

B - DISTINCT keyword makes a group function consider duplicate values.

C - Group functions ignore null values.

D - None of the above.

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 removing rows from a table?

A - You remove existing rows from a table using the DELETE statement

B - No rows are deleted if you omit the WHERE clause.

C - You cannot delete rows based on values from another table.

D - All of the above.

Q 7 - Which of the following is true about the CREATE TABLE statement?

A - This is a DML statement.

B - This statement also record information in the data dictionary.

C - You don’t need any privilege to use this statement.

D - All of the above.

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

A - They derive data from one table.

B - They contain no functions or grouping.

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

D - All of the above are true.

Q 9 - Which of the following code will retrieve data from the view all_marks_english, created in the previous question?

A - select view all_marks_english;

B - select from all_marks_english;

C - retrieve from all_marks_english;

D - select * from all_marks_english;

Q 10 - Which of the following is true about a role?

A - A role is a named group of related privileges.

B - It can be it can be created and assigned to a user.

C - It can be revoked from a user.

D - All of the above.