title: Looking for exercises to learn SQL, using the Northwind database
body: <p>I am trying to become more familiar with SQL by writing queries against the Northwind database.  </p>
  
  <p>I am looking for some exercises that would help me to learn SQL and features of SQL Server.  It is important that the exercises have solutions, and in complicated cases, it would be great if there was an explanation for the query. </p>
  
  <p>Thanks for the answers so far but I still have not found <em>what</em> I am looking for:
  Is there any free resource, available online, without registration, that I can find a list of these exercises?  </p>