What is the fastest way to compare 2 rows in SQL?

Question

I have 2 different databases. Upon changing something in the big one (i don't have access to), i get some rows imported in my databases in a similar HUGE table. I have a job checking for records in this table, and if any, execute a stored procedure, process and delete from table.

1. Performance. (Huge amount of data) I would like to know what is the fastest way to know if something has changed using let's say 2 imported rows with 100 columns each. Don't have FK-s, don't need. Chances are, that even though I have records in my table, nothing has actually changed.

2. Also. Let's say there is actually changed something. Is it possible for example to check only for changes inside datetime columns?

Thanks

Answer 1

You can always use update triggers - these will give you access to two logical tables, inserted and updated. You can compare the values of these and base your action on the results.