Summarizing Previous(fld) fields

[Stupot2k]

I am trying to calclate an MTBF figure for a number of reported incidents. I am using the Previous(fld)Function to calclate the time elapsed between subsequent records:

( {@actual_clear_datetime}- Previous ({@actual_reported_datetime})) * 24

When I try to summarize the field to work out an average I am ot able to do so. Can anybody help to identify another way of achieving this?

Sample Data:
Reported Cleared Priority Ticket MTBSI MTBF
29/03/2007 25/06/2007 A 0000156634
11/05/2007 13/06/2007 A 0000161175 1,034.45 1,821.52
22/05/2007 21/06/2007 A 0000162283 265.84 979.89
04/06/2007 04/06/2007 B 0000163479 307.44 312.67
04/06/2007 04/06/2007 A 0000163483 0.03 0.78
04/06/2007 05/06/2007 B 0000163523 3.17 27.17
05/06/2007 05/06/2007 B 0000163649 22.13 23.45
11/06/2007 11/06/2007 B 0000164256 140.27 141.12


Many thanks

Stuart

 

[dgillz]

I cannot tell from your data sample which field represents the change from the previous record, but a running total field or variables should do the trick.

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[lbass]

You could use a variable like:

//{@accum} to be placed in the detail section:
whileprintingrecords;
numbervar summtbf := summtbf + {@MBTF};
numbervar cnt;

//{@displ} to be placed in the report footer:
whileprintingrecords;
numbervar summtbf;
numbervar cnt;
if cnt > 0 then
summtbf/0

If you want the average at a group level, you would also need a reset in the group header:

whileprintingrecords;
numbervar summtbf;
numbervar cnt;
if not inrepeatedgroupheader then(
summtbf := 0;
cnt := 0
);

-LB