Q&A for music historians, critics, and fans
select t.tagname from posts p join users u on p.owneruserid = u.id join posttags pt on pt.postid = p.id join tags t on t.id = pt.tagid where p.posttypeid = 1 group by t.tagname having count(case when lower(u.location) like 'nigeria' then 1 end) > 10 and count (case when lower(u.location) like 'iceland' then 1 end) > 15