How to get time interval value from report data in group

[Su]

hi,

I would like to display the datetime interval value from data field.
I am using the standalone report designer and my report has chart and summary data by group. I have tried out the aggregate function but my function will display the interval for inner group only. Kindly help to advise how to get this?

The report data structure would be like the following 
Name,QtyName,DateTime
DV10002,Current Phase B,2016-09-05 00:15:00
DV10002,Current Phase B,2016-09-05 00:30:00
DV10002,Current Phase B,2016-09-05 00:45:00
DV10002,Current Phase B,2016-09-05 01:00:00
DV10003,Current Phase B,2016-09-05 01:00:00
DV10003,Current Phase B,2016-09-05 01:30:00
DV10003,Current Phase A,2016-09-05 01:00:00
DV10003,Current Phase A,2016-09-05 01:30:00

e.g  DV10002 
       Current Phase B
       Interval : 15 mins
       DV10002  Summary 

       DV10003
Current Phase B
Current Phase A
       Interval : 30 mins
       DV10003 Summary 

I have also attached the sample report. 
Thank you

[Todor]

Hello Su,

You may use the Previous Data function to get the Time Difference between two consecutive records, for example with an Expression like:

= Fields.DateTime - Previous("Detail", Fields.DateTime)

The scope "Detail" in the expression denotes the inner-most Report Group.

I have attached a sample report that demonstrates the approach. The first value will be blank since it does not have a previous one.

If the intervals are regular for each group you may consider introducing a dedicated property (e.g. of type TimeSpan) and display it in the group header/footer only once.

Regards,
Todor
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