Some time ago my company was evaluating different reporting solutions. We settled on MS SSRS particularly because it's capable of connecting to various types of data stores, including MS SQL, Oracle and SAP Netweaver BI. It has proven the test of time pretty well, however, we're now under fire from management because SSRS is not capable of mixing data sources into the same data set.
So, I searched long and hard for a reporting solution that can "inner join" data from separate systems, but I came up short. I am about to propose that we custom write reports (ASP.NET) for these cross-system report requests, but I wanted to ping the internet first for any advice.
How do you "inner join" across your massive enterprise systems for reporting purposes?