title: How to get number of days between the earliest date and the oldest date in every row of my input
body: <p>I am having difficulty getting the number of days between the oldest date and the newest date, the problem I have is if I use <code>MIN</code> or <code>MAX</code> I have to group by a column which is an issue as I do not have a column to group by.</p>
  
  <p>If my data looks like this:</p>
  
  <pre><code> 2017/01/01         EXAMPLE 
   2017/01/01         EXAMPLE
   2017/01/01         EXAMPLE
   2017/01/05         EXAMPLE
   2017/01/06         EXAMPLE
   2017/01/06         EXAMPLE
   2017/01/08         EXAMPLE
  </code></pre>
  
  <p>I need to add a column with a static number throughout the table so it looks like:</p>
  
  <pre><code> 2017/01/01         EXAMPLE       8
   2017/01/01         EXAMPLE       8
   2017/01/01         EXAMPLE       8
   2017/01/05         EXAMPLE       8
   2017/01/06         EXAMPLE       8
   2017/01/06         EXAMPLE       8
   2017/01/08         EXAMPLE       8
  </code></pre>
  
  <p>This is probably very simple but I just cannot get it right without grouping - 8 is the number of days between the earliest day and the last day</p>
  
  <p>This is for ORACLE</p>