MetaData Data Mining

I am looking for anyone who can help me find an existing tool that will allow my programming team to build reports and data extracts simply and easily from a form of query builder. Unfortunatley, my database is structured as a metadata store using name data pairs. The actual structure is something like:
DateTime; Customer (integer); fieldname(string); fieldvalue (string)

In addition, I have another table that is structured similarly to store numeric data
DateTime; Customer (integer); fieldname(string); fieldvalue (Integer)

So, for the query tool to even start, it needs to scan both tables for distinct values in the fieldname column for a specific date/time range for a specific customer. Once that is done, it can display the field names and begin to search for the data I am looking for.

In addition, If I want the names of all people in the system who have bought a pie from my customer 1, the query tool will have to search for the fieldvalue "pie", return the key cells and then search for the fieldnames "Name" where the fields match (that or do it in a compound query).

Is there any tool anywhere out there that might have such capabilities?