formula delta figures for group data

[Seven777]

newbie........

I have a report that I need some help with please

What I need to do is to read values from the database and then chart the data. So far no problem... I also want to predict the current trend of the data so as to plot the expected future data. This is where my trouble is.

How do I get the delta between the first two values in a group, then get the delta between the 2nd and 3rd values and so on...... all of this to be used later in the report to calculate the future values.

example.....

data 1 = 0.1
data 2 = 0.2
data 3 = 0.4
data 4 = 0.7
data 5 = 1.0
data 6 = 1.3
data 7 = 1.7

i need to chart these specific values, but i also need to chart the delta between them.

delta chart
point 1 = 0.1
point 2 = 0.2
point 3 = 0.3
point 4 = 0.3
point 5 = 0.3
point 6 = 0.4

prediction.....
point 7 = 1.7 + ( prediction )

info :
the number of 'data' being looked at is not static, for some of the reports it might have 10 data samplings to use, for others it might only have 5.

I am not looking for the predictive formula, as I will eventually determine it , but what I cant seem to get CR to do is to let me store the values of the delta figures for later use....

any help?

 

[dgillz]

{Fieldname}-previous({Fieldname}) will give you the delta on each record. Will that work?

Software Training and Support for Macola, Crystal Reports and Goldmine
251-621-8972
dgilsdorf@mchsi.com

 

[Seven777]

very nice. I knew there was an easy way to do what I have been working on for 3 days

I am new to this forum, but it is a definate bookmark. Thanks for the assistance!