title: Question mark in SAS
body: <p>What does the question mark in SAS mean? </p>
  
  <pre><code>proc print data=employees;
     where name ? W;
  run;
  </code></pre>
  
  <p>I read <a href="http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a000180357.htm" rel="nofollow">here</a> that it is used in the input statement to supress warnings. But in the above example it is in the <code>where</code>. I presume it means <code>contains</code>. What is the difference of using  <code>?</code> in input and <code>where</code>? </p>