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 honours subject is English, or honours subject is Spanish and percentage of marks more than 80?

A - select first_name, last name from students where (honours_subject = “English” or honours_subject = “Spanish” ) and percentage_of_marks > 80;

B - select first_name, last name from students where honours_subject = “English” or honours_subject = “Spanish” and percentage_of_marks > 80;

C - select first_name, last name from students where honours_subject = “English” and honours_subject = “Spanish” or percentage_of_marks > 80;

D - select first_name, last name from students where (honours_subject = “English”) and honours_subject = “Spanish” and percentage_of_marks > 80;

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 - You want to calculate the tax payable by the employees of an organization. If the employee gets a commission, then the tax would be calculated on commission plus salary, if the employee does not get any commission, then the tax would be calculated on salary only. Which function should you use for calculating tax?

A - NVL

B - NVL2

C - NULLIF

D - COALESCE

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 not true about the ALTER TABLE statement?

A - It can add a new row.

B - It can add a new column.

C - It can modify existing columns.

D - It can define a default value for the new column.

Q 8 - Which of the following code will remove all the rows from the table LOCATIONS?

A - DROP TABLE locations;

B - DELETE TABLE locations;

C - TRUNCATE TABLE locations;

D - None of the above.

Q 9 - Which of the following is not true about the Pseudocolumns that return the sequence values?

A - NEXTVAL returns the next available sequence value.

B - CURRVAL gets the current sequence value.

C - PREVVAL gets the previous sequence value.

D - None of the above.

Q 10 - A database administrator can

A - Create users.

B - Create privileges.

C - Grant privileges.

D - All of the above.