title: Converting Time into Minutes in Pentaho (PDI Script)
body: <p>I want to calculate sum of activity time(HH:mm:ss) for various transactions in PDI. For example, consider 3  activity times: 1) Activity 1 - 01:22:03, 
  2) Activity 2 - 01:10:11 and 3) Activity 3 - 00:22:20. The sum of all this time should be 02:54:34 but the result displays negative value. How would I improve it? </p>