title: Spring data jpa + joining 2 tables
body: <p>I have 2 entity classes <code>Product</code> and <code>ProductAltID</code> with no <code>@OnetoMany</code> mapping defined between them.</p>
  
  <p>I want to do something like this</p>
  
  <pre><code>select p from ProductAltid inner join Product pai
  where p.id = pai.id
  </code></pre>
  
  <p>How can I achieve this?</p>