collectiveidea/awesome_nested_set — pull request #99 by joshuaclayton (2011-10-24 16:26:03+00:00)
Title: Fix .all_roots_valid? to work with Postgres.

.all_roots_valid? was using SQL to group and then doing an additional
group_by to group data; however, `roots.group` doesn't work with
Postgres and was raising an ActiveRecord::StatementInvalid because of
how Postgres handles the GROUP BY clause. This removes the group from
SQL completely.

Closes #88