📚 Complete SQL Basics Notes

A beginner-friendly repository containing well-structured SQL notes, examples, and explanations to help students and developers understand Structured Query Language (SQL) concepts from scratch.

This repository is designed for quick revision, interview preparation, and learning SQL fundamentals step-by-step.

SQL is a language used to interact with relational databases, allowing users to create, read, update, and delete data (CRUD operations) efficiently.

🚀 About This Repository

This repository contains simple and clear SQL notes covering important database concepts and commonly used SQL commands.

It is useful for:

• 🎓 Students learning Database Management Systems (DBMS)
• 💻 Beginners starting with SQL
• 🧠 Quick revision before interviews or exams
• 👨‍💻 Developers who want a fast SQL reference

📖 Topics Covered

The repository includes notes on:

1️⃣ Introduction to SQL

• What is SQL
• What is DBMS
• Relational Databases

2️⃣ SQL Commands

• DDL (Data Definition Language)
• DML (Data Manipulation Language)
• DCL (Data Control Language)
• TCL (Transaction Control Language)

3️⃣ Table Operations

• CREATE TABLE
• ALTER TABLE
• DROP TABLE
• TRUNCATE

4️⃣ Data Manipulation

• INSERT
• UPDATE
• DELETE

5️⃣ Data Retrieval

• SELECT
• WHERE
• ORDER BY
• GROUP BY
• HAVING

6️⃣ Joins

• INNER JOIN
• LEFT JOIN
• RIGHT JOIN
• FULL JOIN

7️⃣ Constraints

• PRIMARY KEY
• FOREIGN KEY
• UNIQUE
• NOT NULL
• CHECK
• DEFAULT

8️⃣ Advanced Concepts

• Views
• Indexes
• Sequences
• Set Operations

💡 Example SQL Query

SELECT name, department
FROM employees
WHERE salary > 50000
ORDER BY salary DESC;

This query retrieves employees earning more than 50,000 and sorts them by salary.

🛠 Tools You Can Use With These Notes

You can practice SQL using:

• MySQL
• Oracle SQL
• PostgreSQL
• SQLite
• MySQL Workbench

📂 Repository Structure

├── 📁 Handbook & Code
│   ├── 📄 01_createusertable.sql
│   ├── 📄 02_insertdata.sql
│   ├── 📄 03_foreignkey.sql
│   ├── 📄 04_addadmin.sql
│   ├── 📄 05_log_table.sql
│   └── 📕 MySQL Handbook.pdf
├── 📄 1.mwb
├── 📄 Joins.sql
├── 📄 Keys.sql
├── 📕 MySQL Handbook.pdf
├── 📄 aggregateFunctions.sql
├── 📄 classroom.sql
├── 📄 clauses.sql
├── 📄 college.sql
├── 📄 collegeTwo.sql
├── 📄 companyDatabase.sql
├── 📄 constraints.sql
├── 📄 database_related_queries.sql
├── 📄 exercise.sql
├── 📄 exerciseClausesAlter.sql
├── 📄 joinsExercise.sql
├── 📄 operators.sql
├── 📄 project.sql
├── 📄 questions.sql
├── 📝 readme.md
├── 📄 revisitingSQL.sql
└── 📄 table_related_queries.sql

(Structure may vary depending on files added.)

🎯 Who Should Use This

This repository is ideal for:

• Computer Science Students
• Database Beginners
• Coding Interview Preparation
• Backend Developers
• Data Analysts

🤝 Contributions

Contributions are welcome!

If you'd like to improve the notes:

1. Fork the repository
2. Create a new branch
3. Add your improvements
4. Submit a Pull Request

⭐ Support

If you find this repository useful:

• ⭐ Star the repository
• 🔗 Share it with other learners

👨‍💻 Author

Rishiraj Pathak

Computer Engineering Student
Passionate about Programming, Databases, and Software Development

GitHub:
https://github.com/Rishiraj-Pathak-27