Chart conditional y values

Hi,
I'm trying to create a chart to show mean time to failure for a system, by month. I've built a cube that returns the number of system failures per month. The y value I'm trying to obtain is the number of hours in the month divided by the number of failures for that month. I am trying to use the expression builder (fx below the Value y Series) to check for the month (i.e. if (data["Group/month"]==1){hours = 31*24;} and also to check for a few special cases of the Summery Field (i.e. 0 or null). The problem is the chart works fine with only the Summary Field as the expression, but the moment I put in a single "if" statement, the chart doesn?t work. I have created a cross tab from this same data cube with a "derived measure" and it works fine. I am running BIRT v2.3.2. Someone please help me, I'm pulling my hair out!
Thanks,
Laura

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JasonW

Laura,

This looks like this may be a bug. It would be good if you could log it. As a work around try adding a measure to the cube that has the if statement in it and use the new measure in the chart. I am attaching an example.

Jason

ldavey

Hi Jason,
I will report the bug.
The additional measure doesn't help in my case because I need the count of system failures before I do the division (i.e. month_hours/count_of_failures). I am attaching a copy of my report. The derived measures in the crosstabs are working exactly the way I would like the chart to work (as a matter of fact if I could just have BIRT create a graph from them it would be great!) Do you know of any other way that I might work around this?
Thanks,
Laura

JasonW

Laura,

Any chance you can use the dataset instead of the cube for the chart?
I know the entire crosstab can be converted to a chart but I do not think derived measures are supported. I tried this with the latest build as well and it still is a bug.

Jason