Meaning of JOIN (SQL)

Simple definition

A SQL operation that combines rows from two or more database tables based on a related column between them.

How to use JOIN (SQL) in a professional context

Commonly used in database management to retrieve data spread across multiple tables.

Concrete example of JOIN (SQL)

A query combining a “Customers” table and an “Orders” table: SELECT Customers.Name, Orders.OrderID FROM Customers JOIN Orders ON Customers.CustomerID = Orders.CustomerID;

What are the types of JOINS in SQL?

Common types include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

What is the difference between INNER JOIN and OUTER JOIN?

INNER JOIN returns only matching records, while OUTER JOIN includes non-matching rows with NULL values.

Do JOINS work only on primary keys?

No, they can work on any related columns, but primary keys are often used.
Related Blog articles
Alexandre, bridging the technical gap at Revolut

Alexandre, bridging the technical gap at Revolut

Alexandre works in sales at Revolut. When clients ask technical questions, he doesn't need to...

How to upskill in tech without quitting your job: Le Wagon Canada’s part-time bootcamp

How to upskill in tech without quitting your job: Le Wagon Canada’s part-time bootcamp

You want to move into data, AI, or tech — or deepen the skills you...

Arthur: From lawyer to AI developer at Ubisoft

Arthur: From lawyer to AI developer at Ubisoft

When Arthur graduated from law school after five years of study, the professional world didn't...

      Suscribe to our newsletter

      Receive a monthly newsletter with personalized tech tips.