Combine rows from related tables.
✍️ 3 exercises + code challenge in this lessonA JOIN combines rows from two or more tables using a related column, usually an id.
In the sample database, Orders.CustomerID refers to Customers.CustomerID.
INNER JOIN: only rows with a match in both tables.LEFT JOIN: all rows from the left table, plus matches from the right.RIGHT JOIN: all rows from the right table, plus matches from the left.FULL JOIN: all rows from both tables.Mastering SQL Joins helps you write clean and reliable SQL code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.
SELECT o.OrderID, c.CustomerName, o.OrderDate, o.Status
FROM Orders AS o
INNER JOIN Customers AS c ON o.CustomerID = c.CustomerID
ORDER BY o.OrderDate;Check what you learned in “SQL Joins”.
Join orders to customers.
SELECT * FROM Orders Customers ON Orders.CustomerID = Customers.CustomerID;
What does a JOIN do?
Select OrderID and CustomerName for every order that has a matching customer, sorted by OrderID.
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