Author here. That would work for a count (so perhaps that was a poor example to ...

schneidmaster on June 30, 2015 | parent | context | favorite | on: Using Nested Selects for Performance in Rails

Author here. That would work for a count (so perhaps that was a poor example to choose for this post) but we also use calculated_attributes for many more complex cases (for example, querying the earliest date in 3 columns across 3 tables).

NARKOZ on July 5, 2015 [–]

There is a gem called eager_group that you might find useful.