title: rows between 1 preceding and preceding 1
body: <p>I am new to SQL and I want to know what exactly the function ( rows between 1 preceding and 1 preceding )do in teradata ,I want a simple clarification please ,I am trying to use this function as a testcase  to get the time gaps in history table between start and end date,can anyone help please or provide any useful links.</p>
  
  <pre><code>SELECT DISTINCT CUST_ID
  FROM
  (
  SELECT 
  CUST_ID,
  STRT_dt - 
  MIN(END_dt) OVER (PARTITION BY CUST_ID ORDER BY END_dt
  ROWS BETWEEN 1 PRECEDING AND 1 PRECEDING) AS diff
  FROM table
  QUALIFY diff &gt; 1
  ) dt
  </code></pre>