MySQL Introduction

Last updated: October 19, 2026Oct 19, 2026

MySQL is a free, open-source relational database management system (RDBMS). It stores data in tables and lets you manage that data with SQL. It powers millions of applications, from small blogs to some of the busiest websites in the world.

This tutorial introduces MySQL: what it is, where it came from, which editions and versions exist, how its client-server architecture works, and how to run your first queries.

1. What is MySQL?

• Relational: data lives in tables that are linked by keys.
• SQL-based: you create, read, update and delete data with standard SQL plus some MySQL extras.
• Client-server: a server program (mysqld) holds the data; clients connect to it.
• Open source: the Community Edition is free under the GNU GPL licence; Oracle also sells a commercial Enterprise Edition.
• Cross-platform: runs on Linux, Windows, macOS and in every major cloud.

The name combines My, the name of co-founder Michael Widenius's daughter, with SQL. The dolphin in the logo is called Sakila.

2. A Short History

3. Editions and Versions

4. How MySQL Works: Client-Server Architecture

• Connection layer: accepts network connections (port 3306 by default), checks user name, password and host, and gives each connection a thread.
• SQL layer: parses the SQL, checks privileges, lets the optimizer choose the cheapest plan (for example, which index to use), and executes it.
• Storage engine layer: actually stores and fetches rows. MySQL's special design is that engines are pluggable; InnoDB is the default and supports transactions, row locking and crash recovery.

5. Your First MySQL Queries

Once connected (see MySQL Installation), you can ask the server about itself. These functions work without any table:

SELECT CURRENT_USER() AS user_name, DATABASE() AS current_db, 7 * 6 AS answer;

Result: 1 row

List the databases on the server. A fresh server has only its system databases:

SHOW DATABASES;

Result: 4 rows

Now create a database and a table, add rows and read them back:

CREATE DATABASE cafe;
USE cafe;

CREATE TABLE menu (
  item_id INT AUTO_INCREMENT PRIMARY KEY,
  item    VARCHAR(40) NOT NULL,
  price   DECIMAL(6,2) NOT NULL,
  veg     BOOLEAN DEFAULT TRUE
);

INSERT INTO menu (item, price, veg) VALUES
('Masala Dosa', 120.00, TRUE),
('Paneer Roll', 150.00, TRUE),
('Chicken Biryani', 260.00, FALSE),
('Filter Coffee', 40.00, TRUE);

SELECT * FROM menu WHERE veg = TRUE ORDER BY price;

Result: 3 rows

6. The Built-in System Databases

For example, information_schema can tell you about the table you just created:

SELECT table_name, engine, table_rows
FROM information_schema.tables
WHERE table_schema = 'cafe';

Result: 1 row

7. Who Uses MySQL and Why

MySQL is the "M" in the classic LAMP stack (Linux, Apache, MySQL, PHP/Python/Perl). WordPress, Drupal and many e-commerce platforms run on it, and large companies such as Facebook (Meta), Uber, Booking.com, GitHub and YouTube have used it at huge scale.

• Easy to start: installs in minutes and works on a laptop.
• Fast and reliable: InnoDB handles heavy read-write workloads with crash safety.
• Scales: replication, Group Replication and InnoDB Cluster spread load and protect against failures.
• Huge ecosystem: drivers for every language (JDBC for Java), ORMs such as Hibernate, and countless tutorials.
• Free: the Community Edition costs nothing.

See MySQL Features for a full feature tour.

8. Key Terms You Will Meet

9. Practice Exercises

SELECT item, price FROM menu WHERE price < 150 ORDER BY price;

SELECT ROUND(AVG(price), 2) AS avg_veg_price FROM menu WHERE veg = TRUE;

10. Summary

• MySQL is a free, open-source relational database owned by Oracle since 2010.
• It uses a client-server design: mysqld serves many clients over port 3306.
• The server has a connection layer, an SQL layer and pluggable storage engines (InnoDB by default).
• Choose LTS releases for production; Innovation releases bring new features first.
• You manage everything with SQL: CREATE DATABASE, CREATE TABLE, INSERT, SELECT.