title: Postgres how to implement calculated column with clause
body: <p>I need to filter by calculated column in postgres. It's easy with MySQL but how to implement with Postgres SQL ?</p>
  
  <p>pseudocode:</p>
  
  <pre><code>select id, (cos(id) + cos(id)) as op from myTable WHERE op &gt; 1;
  </code></pre>
  
  <p>Any SQL tricks ?</p>