SQL Quiz Test Online (30 random Questions) 2026

This quick 30-minute challenge consists of 30 random multiple-choice questions designed to test your knowledge across various SQL topics, including the introduction to databases, data manipulation and querying, database design and normalization, advanced SQL concepts, and database administration and security. Whether you’re a beginner or looking to expand your SQL expertise, this quiz will enhance your understanding of database management and querying skills.

0 votes, 0 avg

370

You have 30 minutes to complete the quiz. The timer will start when you click the 'Start Quiz' button. Please ensure you are ready before beginning.

Time is up! Your quiz has ended. Your responses have been submitted automatically.

30 Minutes SQL Quiz Test Online

Welcome to the SQL Quiz! This quick 30-minute challenge consists of 30 random multiple-choice questions designed to test your knowledge across various SQL topics, including the introduction to databases, data manipulation and querying, database design and normalization, advanced SQL concepts, and database administration and security. Whether you're a beginner or looking to expand your SQL expertise, this quiz will enhance your understanding of database management and querying skills.

1 / 30

What is the purpose of database auditing?

A) To encrypt database files

B) To design database schemas

C) To optimize query performance

D) To track and log database activities

2 / 30

What is a 'transaction log' in database management?

A) A method for locking tables

B) A record of all changes made to the database

C) A schema for normalization

D) A record of all database queries

3 / 30

What type of dependency does 3NF eliminate?

A) Partial dependency

B) Multivalued dependency

C) Transitive dependency

D) Circular dependency

4 / 30

What does ER stand for in ER Diagram?

A) Entity Reference

B) Event Reaction

C) External Resource

D) Entity Relationship

5 / 30

How is sensitive data protected in a database?

A) By limiting user access

B) By using encryption

C) All of the above

D) By auditing and monitoring activities

6 / 30

What does the DISTINCT keyword do?

A) Sorts records

B) Deletes duplicate records

C) Filters records

D) Selects unique records

7 / 30

Which statement about stored procedures is true?

A) They can be used to encapsulate complex SQL queries and business logic

B) They are executed automatically on database startup

C) They are automatically optimized for performance by the database

D) They cannot accept input parameters

8 / 30

What is the purpose of the WHERE clause in SQL?

A) To sort data

B) To join tables

C) To create indexes

D) To filter records

9 / 30

What is the primary focus of the 5th Normal Form (5NF)?

A) Eliminating partial dependencies

B) Removing join dependencies

C) Eliminating composite keys

D) Ensuring atomic columns

10 / 30

What is the difference between symmetric and asymmetric encryption in databases?

A) Symmetric encrypts only text; asymmetric encrypts all data

B) Symmetric uses one key; asymmetric uses two keys

C) Asymmetric is faster than symmetric

D) There is no difference

11 / 30

What does the NOT IN operator do?

A) Excludes values from a list

B) Joins tables

C) Sorts rows

D) Filters rows

12 / 30

What does the SELECT * statement do?

A) Selects specific columns

B) Selects all columns from a table

C) Selects unique rows

D) Selects all tables

13 / 30

What is the purpose of an index in SQL?

A) To speed up data retrieval

B) To sort data

C) To store duplicate data

D) To ensure data integrity

14 / 30

What is the difference between DELETE and TRUNCATE?

A) DELETE is faster than TRUNCATE

B) DELETE resets indexes; TRUNCATE does not

C) DELETE removes specific rows; TRUNCATE removes all rows

D) DELETE removes all rows; TRUNCATE removes specific rows

15 / 30

What is a primary key?

A) A duplicate identifier for a table record

B) A unique identifier for a table record

C) A command to fetch records

D) None of the above

16 / 30

What is the main difference between a UNION and a UNION ALL?

A) UNION merges columns; UNION ALL merges rows

B) UNION removes duplicates; UNION ALL does not

C) UNION ALL removes duplicates; UNION does not

D) UNION is faster than UNION ALL

17 / 30

What is a window function in SQL?

A) A function that operates on a subset of rows

B) All of the above

C) A function that performs calculations across a window of rows

D) A function that partitions data for analysis

18 / 30

What is a foreign key?

A) None of the above

B) A unique identifier for a table

C) A backup key

D) A key linking two tables

19 / 30

What is the purpose of the EXISTS clause in SQL?

A) To create a temporary table

B) To verify the presence of rows in a subquery

C) To optimize queries

D) To check if a table exists

20 / 30

Which of the following best describes a self-join?

A) A join between two different tables

B) A join that excludes null values

C) A join that merges columns

D) A join of a table with itself

21 / 30

What does 'principle of least privilege' mean in database security?

A) Encrypting sensitive data

B) Assigning minimum access necessary for users

C) Removing unused tables and columns

D) Allowing all users full database access

22 / 30

What is the primary purpose of a database schema?

A) To define the structure of the database

B) To grant user permissions

C) To store backup files

D) To execute SQL queries

23 / 30

What happens if a table is not normalized?

A) Improved performance

B) Elimination of relationships

C) Reduced storage usage

D) Increased redundancy and anomalies

24 / 30

How does the LAG() function work in SQL?

A) Returns the next value in a set

B) Returns the average value of a set

C) Computes a running total

D) Returns the previous value in a set

25 / 30

What is the primary role of a database administrator (DBA)?

A) Developing mobile applications

B) Designing user interfaces

C) Writing application code

D) Managing and securing the database system

26 / 30

What does a foreign key represent in a database?

A) A default value for columns

B) A key that cannot be used

C) A reference to a primary key in another table

D) A unique identifier for each record

27 / 30

What is the purpose of the UNION operator?

A) Deletes records

B) Filters duplicate rows

C) Combines results of two queries

D) Joins tables

28 / 30

What is the maximum number of primary keys a table can have?

A) Unlimited

B) 1

C) None

D) 2

29 / 30

Which normal form is also known as 2NF with additional conditions?

A) BCNF

B) 5NF

C) 4NF

D) 3NF

30 / 30

What does the term 'atomicity' refer to in normalization?

A) Data is stored in multiple columns

B) Each cell contains a single, indivisible value

C) Data is stored in one table

D) Data contains multivalued attributes

Your score is

The average score is 56%

Rate Your Experience!

Anonymous feedback

Thank you for your feedback! We appreciate your input.

10 Minutes MongoDB Quiz Test Online

10 Minutes Docker Quiz Test Online

CSS Quiz Test Online (30 random Questions)

10 Minutes SQL Quiz Test Online

JSON Quiz Test Online (30 random Questions)

HTML Quiz Test Online

Related