There are various ways to find unanswered questions on a site, but all those ways come to totally different results and I'd like to understand why this is. Note that I am very well aware that under some circumstances SE defines "unanswered" as having no upvoted or accepted answers. I'm not here to discusss this notion and its advantages. In this question I am concentrating solely on questions with no (undeleted) answer at all. Also forgive me if this is actually a duplicate, but I'd like to reach a somewhat exhaustive conclusion on the matter here.
So let's take a look at how we can find questions with no answer and let's take this site here (including the different numbers at the time of asking):
- 'Questions' section, 'unanswered' tab: 8,074.
- 'Unanswered' section, 'newest' tab: 7,868.
- 'Unanswered' section, 'no answers' tab: 7,823.
- searching for
is:question answers:0 closed:no: 7,832.
- searching for
is:question answers:0: 15,238.
I know that some of those things ought to be different, e.g. 2 has more than 3 because it includes 0-score unaccepted answers, and 5 has more than 4 because it includes closed ones. However, I included those queries here to maybe see some correlation to other queries, but there is none. For example why is 1 different from all of 2, 3 and 4? What are the additional conditions those different queries operate under?
And last but not least, what is the best and most reliable solution to find each and every non-closed undeleted question that doesn't have any undeleted answers, disregarding any question votes or whatever?