title: Count number of rows that are not within 10 seconds of each other
body: <p>I track web visitors. I store the IP address as well as the timestamp of the visit.</p>
  
  <pre><code>ip_address    time_stamp
  180.2.79.3  1301654105
  180.2.79.3  1301654106
  180.2.79.3  1301654354
  180.2.79.3  1301654356
  180.2.79.3  1301654358
  180.2.79.3  1301654366
  180.2.79.3  1301654368
  180.2.79.3  1301654422
  </code></pre>
  
  <p>I have a query to get total tracks:</p>
  
  <pre><code>SELECT COUNT(*) AS tracks FROM tracking
  </code></pre>
  
  <p>However, I now want to disregard visits from users that have visited multiple times within 10 seconds of each visit. Since I don't consider this another visit, its still part of the first visit.</p>
  
  <blockquote>
    <p>When the ip_address is the same, check
    timestamp and only count those rows
    that are 10 seconds away from each
    other.</p>
  </blockquote>
  
  <p>I am having difficulty in putting this into a SQL query form, I would appreciate any help on this!</p>