Find all open questions that have exactly one particular tag of your choosing and no others
Q&A for linguists, etymologists, and serious English language enthusiasts
-- select Id, Id as [Post Link] from Posts where Posts.PostTypeId = 1 and -- post is a question Posts.ClosedDate is null and -- question is still open Id in ( select PostId from PostTags group by PostId having count(PostTags.TagId) = 1 )