Hi, there

I have a question regarding PL/SQL programming. Reference the following table:
Part No. Case No.
p1 | c1
p2 | c1
p3 | c2
p3 | c2
I need to find whether there is duplication of part No. under the same case No. In the above case, p3 c2 are duplicated. Now I have a program fetching each record from a cursor in a loop. In the loop I want to write this checking. Is there optimized way to write this?