Chart query help

Sergej

Hi!
How to make query type of chart show sum of data by moths?

I have a query that displays 3 items
Date Amount
21.09.2012 500
22.09.2012 600
22.09.2012 400

I changed the type to a chart:
Chart type- Line
Data for X axis - DateShortcut Format-MMMM
Data for Y axis - Amount Type of bar

I expected to see 1 bar September with amount 500+600+400=1500

But I see 2 bars of September with amount 500 and 600. Amount of 400 is not shown at all. Why?

Is it possible to do that with queries?

Sergej

Tried to make query with custom presentation, but getting error

NESTED BY :
org.jfree.data.general.SeriesException: You are attempting to add an observation for the time period 22-Сентябрь-2012 but the series already contains an observation for that time period. Duplicates are not permitted. Try using the addOrUpdate() method.

aware_support

Check how this is done in sample applications - CRM, for example