Repeated Instrument Tests - need to populate a current field with field from previous test
I get several CSV files daily of test results from several thousands electronic modules. So far my input script increments a Test Number field on each input, and each module is defined by a unique number. I've been trying for a couple of days to figure out how to add the previous test result to the current failure list, so I can determine modules that have not been repaired since the last test. I would also like to be able to determine how many failures from the previous test have been resolved (module number still in table, but passing tests now). I would be most grateful for any advice that could steer me towards a (hopefully not too complicated) solution.