title: mysql total working hours
body: <pre>id     title                              start                    end
  1   Doing Coding for this project.  2013-04-02 02:00:00     2013-04-02 04:00:00
  2   Doing Coding for this project.  2013-04-02 04:00:00     2013-04-02 06:00:00
  3   Doing Coding for this project.  2013-04-02 06:00:00     2013-04-02 06:30:00</pre>
  
  <p>I have above <code>MySQL</code> database table record. Now i want to get the total number of <code>hours.</code></p>
  
  <p>I am developing <code>TimeSheet Management Application</code> and <strong>we need to display total working hours with minutes and second of employee. (i.e 04:30:00 according to data i share)</strong></p>
  
  <p><strong>what i have tried?</strong></p>
  
  <p><code>SELECT HOUR(TIMEDIFF(end,start)) AS 'totalHour'</code> but works only for each row not on all records.</p>
  
  <p>I have also tried <code>TIMESTAMPDIFF</code>.</p>
  
  <p>Is this possible?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>From the answer i have received from people i have tried every single of them but everytime i just get <code>4</code> or <code>4.5000</code> but it should return <code>06:30:00</code>.</p>