SQL Joins Explained

INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN

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A JOIN clause is used to combine rows from two or more tables, based on a related column between them (such as a foreign key).

The 4 Types of SQL Joins

1INNER JOIN: Returns records that have matching values in both tables.

2LEFT JOIN: Returns all records from the left table, and matched records from the right table.

3RIGHT JOIN: Returns all records from the right table, and matched records from the left table.

4FULL OUTER JOIN: Returns all records when there is a match in either left or right table.

INNER JOIN Orders and Customers

Try It Yourself »

SELECT 
  Orders.OrderID, 
  Customers.CustomerName, 
  Orders.OrderDate,
  Orders.TotalAmount
FROM Orders
INNER JOIN Customers 
  ON Orders.CustomerID = Customers.CustomerID
ORDER BY Orders.OrderDate DESC;

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Test Yourself With Exercise

+15 XP

Which JOIN returns ALL rows from the left table, even if there are no matches in the right table?

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