How to calculate total time taken by a report

Question

I am a beginner in oracle reports,
I want to display in my report these three fields
Report Start Time:
Report End Time:
Time Taken
Although we can find this by Porgrame->Tracing optinon but i want it should display along with my report. Can somebody help me on that.

Answer 1

I played around with Raffy's idea for a while, but either because I have an older version of Reports (3.0.5), or I interpreted it wrong, my value in CF_END_TIME was always identical to CP_START_TIME. Even when I put the CF_END_TIME column lower and to the right of any other object in the Data Model.
But I did get it to work, and this is how:
I created a Placeholder column named CP_START_TIME that I loaded with SYSDATE in a function on the Before Report Trigger.
I created a Placeholder column named CP_END_TIME that holds a Date. Then I created a Function Column named CF_ADVANCE_END_TIME that I placed inside the lowest Group Field on my Data Model. This function does nothing more than copy SYSDATE into :CP_END_TIME.
Then I created a Function Column called CF_TIME_TAKEN that compares CP_START_TIME to CP_END_TIME and returns a VARCHAR2 string with the elapsed time.
I put the three non-group Columns on my Trailer page and it looks like:
START TIME Oct 12, 2005 14:47
END TIME Oct 12, 2005 16:00
ELAPSED TIME 0 01:12:47
It bears repeating that the Format Mask of the Placeholder Column needs to specify the smallest increment of time you want measured. That Format Mask is used for Validation, and may truncate your date/time if you don't specify all the fields. I used 'Mon DD, YYYY HH24:MI:SS' for my Placeholder columns, and 'Mon DD, YYYY HH24:MI' for the fields that display them.