title: Join vs. sub-query
body: <p>I am an old-school MySQL user and have always preferred <code>JOIN</code> over sub-query. But nowadays everyone uses sub-query, and I hate it; I don't know why.   </p>
  
  <p>I lack the theoretical knowledge to judge for myself if there is any difference. Is a sub-query as good as a <code>JOIN</code> and therefore is there nothing to worry about?</p>