To make it easier to explain my question, here is a sample record set:
I want to query a table like this (but with many more records) to find which uids have more than one entry for the same pid, e.g. for the example above, the result would be "2". I don't need to know how many duplicates there are, nor what the duplicate pids are. I just need to know which uids have duplicate pids.
Also, unlike the example, the pids are not necessarily sequential.
Is this possible?