I have a report requiring two different data sources be compared in one
data region. For example, I'm comparing a measure for a client against
a national average. The client measure comes from one cube and the
national average is stored in a sql database. RS won't allow two data
sources to be used in a data region unless you can use an aggregate
function on the second data source. I attempted to solve this by
creating a cube for the second data source (national averages) and then
a virtual cube to make one data source (i.e. one MDX statement from the
virtual cube per data region) for RS. The orginal MDX used for the
first data source required slicing by dimensions not included in the
national average cube and visa versa. I have been able to get the
correct answer for each cube before combining into the virtual cube,
but I can not get the measures correctly in the virtual if, for each
measure, I need to slice by a dimension that is not shared. I haven't
been able to find the information anywhere (and I've tried internet and
2 books), but because my measures are not correct I assume that a
virtual cube in only useful if the correct results are obtained by
slicing into only the shared dimensions? Are there any other solutions
to the rediculous RS limitation of only being able to provide one data
source to a data region? What we they thinking????

oops, should have used spell check before submitting. it is a
ridiculous RS limitation.

The answer is to create a calculated member using the ValidMeasure
function for each measure in the virtual cube. Just in case anyone is
interested....