This posts gives detailed rules about deleting questions: How does deleting work? What can cause a post to be deleted, and what does that actually mean? What are the criteria for deletion? (I will also include link to the current revision.)
In the part about auto-deletion script I read that:
The system will automatically delete closed (not as a duplicate), unlocked questions with zero or negative score having no upvoted or accepted answers or pending reopen votes, that were closed 9 or more days ago and haven't been edited in the past 9 days.
In the part about self-deleting question I read that:
You can’t delete your own question when it:
- has an upvoted answer, or
- has an accepted answer, or
- has multiple answers (even if there are no upvotes)
So in both cases the phrase "upvoted answer" is used. But an experienced user told me that in case of auto-deletion the score rather than number of upvotes is taken in to consideration. In the case of self-deletion the phrase upvoted answer literally means an answer which has no upvotes. (So if this interpreation is correct, you cannot delete your question which has one answer with zero score, if this score was reached by 5 upvotes and 5 downvotes.)
Is this interpretation correct? Does upvoted answer mean answer with no upvotes or answer with score bigger than zero? Should this really be interpreted differently for these two cases?
EDIT: After suggestion in quid's comment I tested on this question that I was not able to delete it when the single answer was at score 0. (Reached from 1 upvote by somebody else and my downvote. Of course, I later retracted the downvote to quid's useful answer.)