title: How do I write a query to join columns from 3 separate tables in the Northwind database
body: <p>I am working with the Northwind database and trying to write a query that joins 3 separate tables. Here is what I'm trying to do -</p>
  <ol>
  <li>From the <code>Order Details</code> table, I want to get the <code>OrderID, TotalSales = UnitPrice * Quantity</code></li>
  <li>Join the <code>EmployeeID</code> from the <code>Orders</code> table</li>
  <li>Join <code>Name = FirstName+ ' '+LastName</code> from the <code>Employees</code> table</li>
  </ol>
  <p>I am able to write a query to join all 3 tables, however I cannot seem to select the columns calculated columns that I need. Here is the query I'm using to join the 3 tables -</p>
  <pre><code>select a.*, b.*, c.*
  from [Order Details] a 
      inner join Orders b
  on a.OrderID = b.OrderID
      left join Employees c
  on b.EmployeeID = c.EmployeeID
  </code></pre>
  <p>Any help will be much appreciated.</p>
  <p><a href="https://i.stack.imgur.com/KXCjo.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KXCjo.png" alt="enter image description here" /></a></p>