Implement a new XML web service, in the web service, use the SharePoint API to merge or join two or more list. Then, in SSRS, retrieve data from the XML web service using XML data source type.
Well I think I'm totally lost with the XML-thing..
Basically I want to join multiple SP lists to use em as a data source in Report Builder 3.0. I'm using SharePoint 2010.
I know how to build the join query in LINQ/CAML. I've done it before using the SharePoint object-model API. So it wouldn't be a problem to do the same using the web services API.
But what about creating a new XML web service? Could someone guide me through this? Any good tutorials/examples from the very basics would be greatly appreciated.