ruby - 续集:如何使用分组和计数

Question

简单地说，我如何使用 Sequel 执行此查询？

select a.id, count(t.id)
from albums a
right join tracks t on t.album_id = a.id
group by a.id

Answer 1

DB[:albums___a].
  right_join(:tracks___t, :album_id=>:id).
  select_group(:a__id).
  select_more{count(:t__id)}