Q&A for those involved in the field of teaching Computer Science
SELECT * FROM (SELECT TOP 10 * FROM TAGS ORDER BY Count DESC) AS TopTags LEFT JOIN (SELECT PostTags.TagId, Posts.OwnerUserId, COUNT(*) AS TagCount FROM ( Posts LEFT JOIN PostTags ON Posts.Id = PostTags.PostId ) GROUP BY Posts.OwnerUserId, PostTags.TagId) AS TagCounts ON TopTags.Id = TagCounts.TagId --ORDER BY Reputation