You will find that a small package workbook with some sample data - (just make something up in excel to mimic your data) will help the community to engage and assist. Sorry for the late reply.
I would probably change - ( [THINGS].[field1] = "t" ) to If ( [THINGS].[field1] = "t" ) then 1 end and then wrap a sum() around that field in a calculation over your count of field 2. Note that I would likely double check on the next count statement as well. Without a view of the data you are working with, it is hard to provide speicific calculations.