Q:

Question getting closed for being a duplicate when it's not?

I had this question getting closed for being a duplicate. I don't consider it a duplicate at all. I wasn't asking what the N stands for in SQL but why is the Like operator not returning what I expected. Of course had I known I missed the N, I wouldn't have asked the question plus I wouldn't have found the other question because it wasn't going to be something I was going to search for because I already know what N is used for. I don't know what I don't know.
The question was closed by a single person. Not a group who shared the same opinion. I asked the person who left the useful comment to leave it as an answer so I can credit him. He can't leave an answer.
What's your opinion? Was marking it a duplicate and closing decision valid?

A:

Yes, the question is a duplicate. The closure is correct. The answer to your question is contained in the other question. When two questions have the same answer, they are duplicates.
You claim:

If I knew I am missing the N, I wouldn't have asked the question! Two very different contexts.

The first part of this is certainly true, but irrelevant. Closing a question as a duplicate is not an attack, not a dismissal of the question, and does not carry any implication that you should have never asked the question.
Rather, questions get closed as duplicates by subject-matter experts who can see relationships and commonalities even when others with less experience cannot. It is a way of linking your unanswered question with an existing Q&A that already provides the answer. In some cases, seeing that link does require some expertise, or even assume that one already knows the answer to the question. That isn't a problem, and doesn't make the duplicate closure incorrect.
Context is not particularly important. That you arrived at the need to use/understand the 'N' prefix differently is true enough, but you still need to use the 'N' prefix. Even you agree with that, after reading Tim Biegeleisen's comment. All that matters is whether the answer to your question can be found in the answers to the other question. The goal of this site is to find an answer, after all.
There would be no advantage in having your question remain open with an answer posted by Tim Biegeleisen or anyone else that said "use the 'N' prefix on your Unicode string" over having your question marked as a duplicate of an existing, canonical question that explains what the 'N' prefix is, when it should be used, and why it provides support for Unicode characters in strings. At a minimum, they are both equally useful. In general, the latter is far more useful than the former because it groups related information together in one place, making it easier to find and curate. It also provides a greater depth of explanation than a one-off answer might.
You could argue that the answer to use an 'N' prefix with your LIKE operator should itself contain a link to the other question, which would then serve the goal of providing context and additional information. While that is certainly an acceptable approach, I do not see how it provides any advantage over closing the question directly as a duplicate. In either case, you get your answer. Closing it as a duplicate reduces pointless duplication and repetition. It also allows the solution to be more easily kept up-to-date (e.g., if future releases of SQL Server introduce an 'NX' operator that provides similar functionality with better performance or whatever).

