title: Mysql - wierd join query
body: <p>Is it possible in MySQL to join a?</p>
  
  <p>For example, say I have the following sub query:</p>
  
  <pre><code>select username, password from users
  </code></pre>
  
  <p>I want to use the fields in an update as follows:</p>
  
  <pre><code>update test_users set password = { result from subquery } where { result from subquery.user } = 100;
  </code></pre>
  
  <p>This is a silly example but only used to illustrate the point.</p>
  
  <p>Essentially my sub query returns two columns and I need to use them in an update.</p>