Comparing data of 2 lists

Hi Experts,
I want to compare data of 2 lists.
List 1 contains data Id=1, Amt=100, Quantity=2, Name=A
List 2 contains data Id=1, Amt=200, Quantity=3, Name=A
I want to get data in List 3 only changed data i.e. Amt=200, Quantity=3 and save that data in database.
Please help, how can I compare the same.
Thanks,
Rahul