rails/arel — pull request #142 by sunaku (2012-09-22 23:02:49+00:00)
Title: to_sql: add support for emitting SQL subqueries

Added support for running `#to_sql()` on an Arel query tree that contains nested subqueries (Arel::SelectManager), which themselves may contain nested subqueries, *ad infinitum*. :cake: