Q&A about the site for biology researchers, academics, and students
select t.tagname, count (distinct p.owneruserid) as Users from users u, posts p, posttags pt, tags t where p.owneruserid = u.id and p.posttypeid = 2 and p.score > 0 and pt.postid=p.ParentId and t.id = pt.tagid and (t.tagname='c' OR t.tagname='java' OR t.tagname='mysql' OR t.tagname='c#') group by t.tagname