title: Table name prefix for columns in UPDATE query
body: <p>Is table name prefix for fields to be update not allowed in <code>SQL</code>?  Like:</p>
  
  <pre><code>UPDATE tablename 
     SET tablename.mycolums = true 
   WHERE ...
  </code></pre>
  
  <p>What is the <strong>SQL</strong> standard?</p>