I was wanting to save the results of a filter to an Excel file today, and I found that the filter did not have a "Save As" button. I found an article here that explained it, but I modified the report slightly to fit my needs. I was looking for way to get the list of computers in my Patch Test Group Filter. I used this SQL query to create a report to then save as a .csv:
SELECT Distinct r.Guid AS '_ItemGuid', r.Name AS 'Resource', r.[User], r.[System Type], r.[OS Name], vItem.Name AS FilterName FROM vItem INNER JOIN CollectionMembership INNER JOIN vComputerEx AS r ON CollectionMembership.ResourceGuid = r.Guid ON vItem.Guid = CollectionMembership.CollectionGuid LEFT OUTER JOIN Inv_AeX_AC_Identification ON r.Guid = Inv_AeX_AC_Identification._ResourceGuid WHERE CollectionMembership.CollectionGuid = 'd0fae853-3129-490f-86fd-e8a8bc0162f2' ORDER BY r.Name ASC
All you need to change on this report os the Guid for your required Filter (in the SQL its called a collection still...). You can get the guid of your Filter by right clicking on your desired Filter, and click on "Properties". This will give you the guid to put in this SQL query.
This was exactly what I needed. Although I added a report perameter for the guid so that I would not have to edit the report everytime I needed to check a different filter. I also created one for user based filters too, I just had to change vComputerEX to vUser and remove r.[User, r.[System Type], and r.[OS Name]. Thanks for this acticle it saved me a lot of time figuring out the query on my own!