SQL Quiz

Welcome to the SQL Quiz page by The Coding College! Test your SQL knowledge with this interactive quiz designed for learners at all levels. Whether you’re a beginner brushing up on basics or a professional honing your skills, this quiz will challenge your understanding and help you master SQL concepts.

Why Take an SQL Quiz?

SQL quizzes are a fun and engaging way to:

  • Reinforce Learning: Apply what you’ve learned in real-world scenarios.
  • Identify Weaknesses: Discover areas where you need more practice.
  • Prepare for Interviews: Boost your confidence with practice questions.
  • Stay Updated: Stay sharp with current SQL trends and techniques.

Instructions

  1. Read each question carefully.
  2. Select the best answer from the options provided.
  3. Check your score at the end of the quiz.

SQL Quiz Questions

Question 1: Basic SELECT Statement

Which SQL statement is used to retrieve all records from the Customers table?

  • A) GET * FROM Customers;
  • B) FETCH ALL FROM Customers;
  • C) SELECT * FROM Customers;
  • D) RETRIEVE * FROM Customers;

Answer: C) SELECT * FROM Customers;

Question 2: Filtering with WHERE Clause

How would you write a query to find all customers from Germany in the Customers table?

  • A) SELECT * FROM Customers WHERE Country = 'Germany';
  • B) SELECT Country FROM Customers = 'Germany';
  • C) GET ALL FROM Customers WHERE Country = Germany;
  • D) SELECT * FROM Customers FILTER Country = 'Germany';

Answer: A) SELECT * FROM Customers WHERE Country = 'Germany';

Question 3: Using Aggregates

Which SQL function is used to count the total number of rows in a table?

  • A) COUNT(*)
  • B) SUM(*)
  • C) TOTAL(*)
  • D) ADD(*)

Answer: A) COUNT(*)

Question 4: Sorting Data

What does the following query do?

SELECT * FROM Employees ORDER BY Salary DESC;
  • A) Retrieves all employees and orders them alphabetically by name.
  • B) Retrieves all employees and orders them by salary in ascending order.
  • C) Retrieves all employees and orders them by salary in descending order.
  • D) Retrieves employees with the highest salary.

Answer: C) Retrieves all employees and orders them by salary in descending order.

Question 5: SQL Joins

Which SQL JOIN is used to return all records from the left table and matching records from the right table?

  • A) INNER JOIN
  • B) FULL JOIN
  • C) LEFT JOIN
  • D) RIGHT JOIN

Answer: C) LEFT JOIN

Advanced Questions

Question 6: Using GROUP BY

What does the GROUP BY clause do in SQL?

  • A) Groups tables together for a JOIN operation.
  • B) Organizes records into groups based on column values.
  • C) Removes duplicate rows from a table.
  • D) Combines multiple tables into one.

Answer: B) Organizes records into groups based on column values.

Question 7: SQL Injection

Which practice helps prevent SQL Injection attacks?

  • A) Avoiding WHERE clauses.
  • B) Using parameterized queries.
  • C) Using SELECT * in every query.
  • D) Disabling SQL logs.

Answer: B) Using parameterized queries.

Question 8: Creating a Table

Which query correctly creates a table named Students with columns ID (primary key) and Name?

  • A)
CREATE TABLE Students (ID INT PRIMARY KEY, Name VARCHAR(100));
  • B)
MAKE TABLE Students (ID INT KEY PRIMARY, Name TEXT(100));
  • C)
CREATE TABLE Students {ID PRIMARY INT, Name CHAR[100]};
  • D)
NEW TABLE Students (ID INT, PRIMARY, Name VARCHAR(100));

Answer: A)

CREATE TABLE Students (ID INT PRIMARY KEY, Name VARCHAR(100));

Quiz Results

  • 0–3 Correct: Beginner. Revisit the basics to strengthen your foundation.
  • 4–6 Correct: Intermediate. You’re getting the hang of SQL!
  • 7–8 Correct: Advanced. You’re an SQL pro!

Conclusion

Taking SQL quizzes regularly is a great way to solidify your skills and track your progress. Keep practicing to master SQL concepts and boost your confidence in real-world scenarios.

For more SQL quizzes, tutorials, and resources, visit The Coding College.

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