title: Is 'IS DISTINCT FROM' a real MySQL operator?
body: <p>In one book I see this syntax: </p>
  
  <pre><code>SELECT * FROM inw WHERE id IS DISTINCT FROM 4;
  </code></pre>
  
  <p>But I get an error: </p>
  
  <blockquote>
    <p>ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DISTINCT FROM 4' at line 1</p>
  </blockquote>
  
  <p>It's an alternative for: </p>
  
  <pre><code>mysql&gt; SELECT * FROM inw WHERE id is null OR id &lt;&gt; 4;
  +------+
  | id   |
  +------+
  | NULL |
  | NULL |
  |    3 |
  +------+
  </code></pre>
  
  <p>Is 'IS DISTINCT FROM' a real MySQL operator?</p>