How do you join two tables? Please give an example.

In SQL, joining two tables allows you to combine rows that share a related column. The most common join types are INNER JOIN, LEFT (OUTER) JOIN, RIGHT (OUTER) JOIN, and FULL (OUTER) JOIN. For example, suppose you have a Customers table (CustomerID, Name) and an Orders table (OrderID, CustomerID, OrderDate). To retrieve all orders along with the customer name, you would write:

SELECT c.CustomerID, c.Name, o.OrderID, o.OrderDate

FROM Customers c

INNER JOIN Orders o ON c.CustomerID = o.CustomerID;

This INNER JOIN returns only rows where a matching CustomerID exists in both tables. If you want to include customers who have no orders, use a LEFT JOIN:

SELECT c.CustomerID, c.Name, o.OrderID, o.OrderDate

FROM Customers c

LEFT JOIN Orders o ON c.CustomerID = o.CustomerID;

The LEFT JOIN returns all customers, and NULLs appear for OrderID and OrderDate when there is no matching order. Understanding these join types is essential for querying relational data effectively.