title: What is the difference between preceding and following in teradata query
body: <p>I am confused why we use this min function.I am not able to understand how the below snippet works.Please guide</p>
  
  <pre><code>COALESCE( min((start_Date)) OVER (partition by Seq_id  ORDER BY start_Date rows between 1 following and 1 following),cast( '9999-12-31 00:00:00' as timestamp(6))  end_Date FROM table.test1
  </code></pre>