MySQL Tutorial

MySQL is one of the most popular open-source relational database management systems (RDBMS). It is widely used in web applications, data storage, and business systems. Whether you are a beginner or an aspiring developer, learning MySQL gives you the foundation to work with data effectively. This tutorial covers the basics of MySQL in simple terms.

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What is MySQL?

MySQL is a relational database management system developed by Oracle. It stores data in tables that are related to each other using keys. MySQL uses Structured Query Language (SQL) to manage and manipulate data.

• Relational: Data is organized into rows and columns.
• Open-source: Free to use with large community support.
• Cross-platform: Works on Windows, Linux, and macOS.
• Widely used: Powers platforms like WordPress, Facebook, and YouTube.

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Why Learn MySQL?

1. Easy to learn – Beginner-friendly commands.
2. High performance – Handles large databases efficiently.
3. Secure – Provides authentication and access control.
4. Compatible – Works with programming languages like PHP, Java, Python, and Node.js.
5. In-demand skill – Used in web development, data science, and enterprise applications.

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Installing MySQL

You can install MySQL in two common ways:

1. Download MySQL Community Server from the official MySQL website.
2. Install XAMPP or WAMP package, which includes MySQL along with Apache and PHP for web development.

Once installed, you can access the MySQL command-line client or use tools like phpMyAdmin and MySQL Workbench for a graphical interface.

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Basic MySQL Commands

Here are some essential SQL commands you will use frequently:

1. Creating a Database

CREATE DATABASE school;

2. Using a Database

USE school;

3. Creating a Table

CREATE TABLE students (
    id INT PRIMARY KEY AUTO_INCREMENT,
    name VARCHAR(50) NOT NULL,
    age INT,
    grade VARCHAR(10)
);

4. Inserting Data

INSERT INTO students (name, age, grade)
VALUES ('Riya', 14, '8th'),
       ('Amit', 15, '9th');

5. Viewing Data

SELECT * FROM students;

6. Updating Data

UPDATE students
SET grade = '10th'
WHERE name = 'Amit';

7. Deleting Data

DELETE FROM students
WHERE id = 1;

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MySQL Data Types

• Numeric: INT, FLOAT, DECIMAL
• String: CHAR, VARCHAR, TEXT
• Date/Time: DATE, DATETIME, TIMESTAMP

Choosing the correct data type is important for performance and storage optimization.

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Keys in MySQL

Keys are used to uniquely identify and relate data.

• Primary Key: Unique identifier for a record (e.g., id).
• Foreign Key: Links one table to another.
• Unique Key: Ensures no duplicate values.

Example:

CREATE TABLE courses (
    course_id INT PRIMARY KEY,
    course_name VARCHAR(50)
);

CREATE TABLE enrollments (
    student_id INT,
    course_id INT,
    FOREIGN KEY (student_id) REFERENCES students(id),
    FOREIGN KEY (course_id) REFERENCES courses(course_id)
);

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Clauses in MySQL

• WHERE – Filter records.

SELECT * FROM students WHERE age > 14;

• ORDER BY – Sort results.

SELECT * FROM students ORDER BY name ASC;

• GROUP BY – Group rows for aggregation.

SELECT grade, COUNT(*) FROM students GROUP BY grade;

• HAVING – Add conditions on groups.

SELECT grade, COUNT(*) 
FROM students 
GROUP BY grade 
HAVING COUNT(*) > 1;

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Joins in MySQL

Joins are used to combine data from multiple tables.

• INNER JOIN – Matches records in both tables.

SELECT students.name, courses.course_name
FROM students
INNER JOIN enrollments ON students.id = enrollments.student_id
INNER JOIN courses ON enrollments.course_id = courses.course_id;

• LEFT JOIN – Returns all records from the left table, even if no match exists.
• RIGHT JOIN – Returns all records from the right table.
• FULL JOIN – Combines results of LEFT and RIGHT joins (not directly supported in MySQL, but can be simulated).

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Advantages of MySQL

• Free and open-source
• Fast and reliable
• Scalable for small and large applications
• Cross-platform support
• Widely adopted by developers and enterprises

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Real-World Applications

• Websites: WordPress, Joomla, Drupal
• E-commerce: Magento, WooCommerce
• Social Media: Facebook, Twitter (early versions)
• Banking & Finance: Secure transaction handling

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Conclusion

MySQL is an essential tool for developers, analysts, and businesses that need to manage structured data. With simple SQL queries, you can create, manage, and analyze databases effectively. Once you master the basics—like creating databases, inserting data, and using joins—you’ll be ready to handle more advanced concepts such as indexing, stored procedures, and transactions.

Whether you want to build dynamic websites, create enterprise apps, or step into data science, learning MySQL is a must-have skill.