title: how to subtract days or months from datetime using postgresql/netezza
body: <p>I have this sql query that is working fine but would like to convert it into some kind of postgresql or netezza equivalent query.  Here are my queries:</p>
  
  <pre><code>SELECT name, location, Date FROM myTable WHERE [Date] &lt; DateAdd(hh, 48, [shipDate]
  </code></pre>
  
  <p>and other query</p>
  
  <pre><code>SELECT name, location, Date FROM myTable WHERE [Date] &lt; DateAdd(d, 90, [shipDate]
  </code></pre>