SQL Server Join Challenges - Practical Coding Exercises

Write an Inner Join Query

Write a query to find all orders along with the customer names who placed them using an inner join.

Expected output: A list of orders with corresponding customer names.

Hint: Join Orders and Customers tables on CustomerID.

Use Left Outer Join to Find Customers Without Orders

Write a query to list all customers and indicate which customers have not placed any orders.

Expected output: A list of all customers with NULL in order columns for those without orders.

Hint: Use LEFT JOIN and filter for NULL order IDs.

Create a Self Join to List Employees and Their Managers

Write a query to show each employee's name alongside their manager's name.

Expected output: A list of employees with their respective managers.

Hint: Join Employees table to itself using ManagerID and EmployeeID.

INNER JOIN returns only rows with matching values in both tables, while OUTER JOIN returns all rows from one table and matched rows from the other, filling with NULLs where there is no match.

A self join is used to join a table to itself, typically to query hierarchical data or compare rows within the same table, such as finding employees and their managers.

A CROSS JOIN returns the Cartesian product of two tables, combining every row from the first table with every row from the second. It should be used only when all combinations are needed.