gistfile1.sql

select
  td.tid, td.name, count(n.nid) as cnt
from `term_data` as td
  inner join `content_field_author` ca on ca.field_author_value = td.tid
  inner join node n on n.nid = ca.nid
where (td.vid = 2 and n.type = 'article')
      and (n.created >= 1396310400 and n.created <= 1398816000)
group by n.nid
order by cnt desc;