SQL Join Challenges - Mastering SQL Joins with Practical Exercises

Find Customers with Orders

Write an SQL query using INNER JOIN to list all customers who have placed at least one order.

Expected output: A list of customer names with their corresponding order IDs.

Hint: Join Customers and Orders on CustomerID and select customer names and order IDs.

List All Customers with Their Orders

Write an SQL query using LEFT JOIN to list all customers and their orders, including customers without orders.

Expected output: A list of all customers with order IDs where available; NULL for customers without orders.

Hint: Use LEFT JOIN from Customers to Orders on CustomerID.

Combine Data with FULL JOIN

Write an SQL query using FULL JOIN to combine two tables showing all records from both, matching where possible.

Expected output: A combined list of all records from both tables with matching rows merged.

Hint: Use FULL JOIN on a common key column.

INNER JOIN returns only rows with matching values in both tables, while LEFT JOIN returns all rows from the left table and matched rows from the right table, including unmatched rows with NULLs.

FULL JOIN is used when you want to return all rows from both tables, matching where possible and including unmatched rows from both sides with NULLs.

By always specifying the join condition using ON or USING clauses to match related columns between tables.