Muhammad,
If you re-read the question, Arjun is trying to get either the multicore part number or the wire part number in the same field. You will also see that he HAS used the same query you recommend as part of his query.
Arjun,
I wonder if you have some sort of refresh problem? I have tried your query exactly as you show it. It works perfectly for me (see the PN column)...
The other alternative is that there is a problem with the release you are using (I used 2015.1 for my test), but I'd be surprised if that's the problem.
Simon