Lists 100 tags with a high close rate and at least 5 closed questions. These tags are "probably" bad tags.
Q&A for people interested in the history and origins of science and mathematics
-- Per Tag Close Rate
-- Lists a selection of tags with a high close rate.
SELECT TOP 100
TagName as [Tag],
COUNT(*) [Total Posts],
COUNT(ClosedDate) [Closed Posts],
100.0 * COUNT(ClosedDate) / count(*) as [Close Rate]
JOIN PostTags ON Tags.Id = PostTags.TagId
JOIN Posts ON Posts.Id = PostTags.PostId
GROUP BY TagId, TagName
HAVING COUNT(ClosedDate) >= 5 -- give the tag a chance to be useful
ORDER BY 100.0 * COUNT(ClosedDate) / COUNT(*) desc