title: Get the number of days between two dates in Oracle, inclusive of the dates
body: <p>I want to get total number of days between two provided dates. I've tried the below query but didn't get the exact different; the last date is not being included.</p>
  
  <pre><code>select (to_date ('15-06-13','dd-MM-yyyy') - to_date('01-02-12','dd-MM-yyyy')) 
    from dual
  </code></pre>
  
  <p>This should return 501 days but it is returning 500 days instead. If I add +1 after calculation, then I'm getting the correct result.</p>
  
  <p>Do I really need to include +1 or is there an alternate approach to get the actual result?</p>