I am fairly new to using functions in excel and I couldn't find anything on what am trying to do so I thought I'd ask.

I have 4 basic columns - New Code, New Value, Old Code, Old Value. I need see if any of the 'values' for the codes have changed. So I basically need to check the new code range to see if it matches an old code and then check to see if the two corresponding 'Values' match. Also I need to identify any old codes that are missing from new code column and vice versa. All of the codes should be unique numbers, but the values are not (if it matters). There are about 6000 rows total. Here is a short example.

New Code New Value Old Code Old Value
10021 0 10022 0
10022 0 10040 10
10040 10 10060 10
10060 10 10061 10
10061 10 10080 10

Again, I am new to all of this and only have exerience using one function at a time (versus a function within a function, or using a result of a function in another function. I'm sure it is fairly simple, but help would be appreciated.

Thanks.