If you need to perform joins between SharePoint lists, try WICE JoinPro.
WICE JoinPro is a powerful tool that allows you to realize all kind of JOIN (inner, full, left, right) between your lists and apply sorting, filtering, grouping and paging options without using SharePoint Designer.
Through its user friendly editor, you will be able to configure your data source defining relations between multiple lists coming from different sites and servers using endless parameters (from 2 to n).
JoinPro has a powerful WebPart that can easily display your data in any SharePoint page.
Get the trial version and check our website for more details!
http://sharepoint.wice-group.com/