title: Calculate difference between 2 dates in SQL, excluding weekend days
body: <p>I would like to build an SQL query which calculates the difference between 2 dates, without counting the week-end days in the result.</p>
  
  <p>Is there any way to format the dates to obtain this result ? For example for Oracle database :</p>
  
  <pre><code>select sysdate - creation_dttm from the_table
  </code></pre>