In Alfresco you can query things, and you can create custom webscripts.
A simple aproach may be to create a custom webscript for querying regarding those parameters and to provide the output in CSV format for example.
In the specific case that you mention, you can obtain the info from Alfresco Search, add name:"PO*" in the box and to filter by creator facet . The number of documents will appear in the facet and in the Alfresco Search results page.
In Alfresco Enterprise you have Insight engine for reporting.