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🧠 SQL Introduction

SQL means Structured Query Language. It is a standardized language used to interact with relational databases.

🎯 What is SQL used for?

SQL allows:

• Create and organize databases (tables, relationships, etc.)

• Read data (with queries like SELECT)

• Add (INSERT), modify (UPDATE) or delete (DELETE) data

• Manage security, access rights and performance

🔧 How does SQL work?

Data is stored in tables, much like a spreadsheet:

• Each line = one record (ex: one user)

• Each column = one field (ex: name, email, age)

Example of user table:

id	name	email
1	Alice	[e-mail]
2	Bob	[e-mail]

📌 Some basic commands:

• SELECT * FROM users; read all data

• INSERT INTO users (name, email) VALUES ('Charlie', '[e-mail]');

• UPDATE users SET email = '[e-mail]' WHERE id = 2;

• DELETE FROM users WHERE id = 1;

🛠️ Where is SQL used?

SQL is used in most modern applications: websites, enterprise software, cloud services, etc. Systems like MySQL, PostgreSQL, SQLite, SQL Server use SQL.