What are Joins?

In relational databases, tables are designed to focus on a single subject or entity, such as customers, orders, or courses. This avoids duplication and makes data easier to manage.

To answer real-world questions, however, you often need to bring those separate tables together.

This is where joins come in.

Instead of storing everything in one large table, databases use a normalized design that breaks data into logical pieces.

• students might store student profiles
• enrollments might track which students joined which classes

These tables are related through a shared column, typically an ID.

Joins can be used to:

• Show each customer along with their purchases
• Combine user accounts with their login history
• Match employees to their departments or roles

In short, joins unlock the full power of relational databases.