Sometimes we need to compare rows for two tables. I have saw many times people were asking this kind of tools, I want such a tool too. I did put some time in designing such a tool, but no good idea.
Compare is just the first step, if possible, the repair is also desired. I want to schedule a job to check the table data periodically. Do you have this special requests?
Quest implement this feature in Shareplex software, very cool feature. It can compare millions of rows in half hours and synchronize them (if only few rows are out of sync).
I already have a table structure compare and repair tool, I will introduce it later.