🗄️ Database Learning Notes

📂 Topics Covered

File Description Status
SQL Basics Basic SQL Queries ✅ Done
SQL Practice Practice Problems ✅ Done
Complete SQL Guide Comprehensive SQL Reference ✅ Done
Normalization 1NF, 2NF, 3NF, BCNF ✅ Done
Relationships & Joins Keys, Joins, Relations ✅ Done
SQL Journey Story Learning Journey ✅ Done

🎯 Quick Reference

Basic Queries

-- Select all
SELECT * FROM users;

-- Select with condition
SELECT name, email FROM users WHERE age > 18;

-- Insert data
INSERT INTO users (name, email) VALUES ('John', 'john@email.com');

-- Update data
UPDATE users SET name = 'Jane' WHERE id = 1;

-- Delete data
DELETE FROM users WHERE id = 1;

JOIN Types

-- INNER JOIN
SELECT * FROM A INNER JOIN B ON A.id = B.a_id;

-- LEFT JOIN
SELECT * FROM A LEFT JOIN B ON A.id = B.a_id;

-- RIGHT JOIN
SELECT * FROM A RIGHT JOIN B ON A.id = B.a_id;

Normalization Quick Notes

📚 Resources

Last Updated: March 2026