title: SQL how to merge records where start date follows end date
body: <p>I have a table of data where there may be multiple entries for a single continuous record. </p>
  
  <pre><code>Empno           StartDate            EndDate         Wdays
  1               2014-07-23           2014-07-23        1
  1               2014-11-07           2014-11-29        15
  1               2014-11-30           2014-12-07        8
  1               2014-12-08           2014-12-19        11
  2               2014-11-15           2014-11-16        2
  </code></pre>
  
  <p>Where the start date follows the end date for the same empno I would like only one record to be displayed as follows.</p>
  
  <pre><code>Empno           StartDate            EndDate          Wdays
  1               2014-07-23           2014-07-23         1
  1               2014-07-23           2014-12-19         34       
  2               2014-11-15           2014-11-16         2
  </code></pre>
  
  <p>I have solved the date issue with the answer shown below, but can anyone assist me with summing the 'Wdays' for each instance</p>