6. JOINS

Activity 6.01: Implementing JOINS

Solution:

1. Look at the tables involved in obtaining and identifying the common columns. If you look closely at the following diagram, you will notice that the data that's required is scattered across not just two tables but three, that is, Orders, OrderItems, and Products.

   In cases like these, we'll have to perform multiple joins, with the first join being between the Orders and OrderItems table to get price details, and the second join being between the OrderItems and Products table to get the product information.

2. In a new query window, implement this logic into the query:

   SELECT Orders.OrderNumber,
   OrderItems.UnitPrice,
   OrderItems.Quantity,
   Products.ProductName
   FROM Orders JOIN OrderItems ON Orders.OrderID =   OrderItems.OrderID 
        JOIN Products ON OrderItems.ProductID = Products.ProductID

   In this query, we joined the Orders and OrderItems tables using the OrderID and joined the Products and OrderItems tables using...