Joined: 19 Dec 2008
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Posts: 9053
Posted: 26 Dec 2014 at 5:55am
it appears that this is a multiple row calculation so what you are trying to do is calculate the difference between a min and max value or only on specific dates?
if specifc date then create a formual field to do it for you
if date= firstdate then value else
if date =secondate then value *(-1)
else 0
sum this (likely at a group level to get your value for that group.
You would really need to explain your entire data set more to get more help though.
Joined: 30 Oct 2012
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Posts: 104
Posted: 29 Dec 2014 at 5:54am
Yes it is a multiple row calculation.
The dates are not specific, rather I need to calculate the difference between the most recent reading and the reading before it. The date is grouped by reading device
Joined: 30 Oct 2012
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Posts: 104
Posted: 29 Dec 2014 at 8:59am
I am almost at a solution, but can't quite get it to work right.
I created a formula field titled DIFF as the following:
if {table.meter_id}= Previous({table.meter_id}) then
({table.reading}) - previous({table.reading}) else
0
When I place this field in the detail section of the report, I get the difference between two fields, but the calculation is returning the difference in the previous row instead of the most recent row.
Joined: 30 Oct 2012
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Posts: 104
Posted: 29 Dec 2014 at 9:35am
I figured it out. I replaced "previous" with "next". I didn't realize "next" was a keyword and to me it seemed like previous would have made the most sense since I was subtracting a value from an earlier date.
I don't exactly understand why the solution I came up with works, but it works, so I'm happy enough.
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