Well pg's answer above tells you what sql query to run.
since you are from a programming background it should be quite easy to automate the process in perl.
Install the following modules
-DBI-1.39
-DBD-ORACLE
-DBI-Shell-11.93 (optional).
Once you have these you can write a perl script to connect to the database and run the query given by PG.
If you are interested ,programming the perl DBI is a book that explains how to to this.
SQL "-" is the most appropriate way,though another one can be writing the output of select * from table to a file and using the diff utility.
HTH
<update :as you can see roger beat me to it :)>