Should old questions with a solution in the comments but no posted answer be answered?

Question

I've been searching through old, unanswered (i.e. zero answers) in the ``mysql-error-1064` tag (just as an example), and I've across several questions that:

1. have been answered in the comments
2. could be answered by making an assumption or two
3. could be flagged as poor-quality questions.

If I'm confident of a solution to a question like this, is it acceptable to answer the question to the best of my ability, or simply leave it alone? I would prefer not to make assumptions about what the OP intended, but in questions like this one, the answer in the comments seems to have interpreted the error message well enough to solve the problem.

How should I approach this? If I post an answer detailing the content of the comments, that reputation shouldn't belong to me (in my opinion) but I still feel the question should be answered. Other discussions about a similar issue don't fully answer my question because I'm specifically referring to old questions. Should I still flag old questions, or forgo it to prevent the flag queue from building up?

EDIT: One possible example of this would be this question, since the answer was basically already in the question and comments. It's not a great example and perhaps not completely necessary, but I marked the answer as community wiki so it can be edited, deleted, etc. as seen fit.

Answer 1

If you think you can do the topic justice and pull useful information from the comments into a complete answer, you should do so - even if that does mean making some assumptions.

Don't forget: you can always take information provided by the asker and edit that into the question as well, potentially turning a poor or incomplete question into something more useful. I'm a big fan of doing this after finding that a speculative answer has correctly identified the problem the asker was actually looking to solve; if this has already happened in the comments, so much the better.

But yeah, if there's no clear solution presented in the comments and you can't make enough of a guess at it to write an answer... Go ahead and vote to close or flag as "Not a Real Question".

Finally, note that old, down-voted, unanswered questions will be automatically deleted in some situations... So, if nothing else, vote.

Answer 2

If you can answer better than the answer already provided, then absolutely, you should answer. If the question was answered in comments, one solution is to take the answer that was worked out in the comments and compile that information into a community wiki answer.

Answer 3

If a question has been answered in the comments and it isn't new/active, I think it's perfectly reasonable to post an answer with the info from the comments. This is a Q&A network, and having answers in the answers is just semantically right.

It's up to you to decide how much additional info to include, whether to make your answer CW, and whether to point out that (at least some of) the info was originally posted by another user. Regardless of what you choose, though, be prepared to deal with some "YOU STOLE THAT ANSWER, YOU ANSWER-STEALING THIEF" comments/downvotes from our more... territorial... community members.