record_filter adds column comparisons across tables
I just released version 0.9.14 of record_filter with a spiffy new feature that allows you to compare columns across tables instead of simply comparing columns against your data. Let’s say you have a Blog class that has_many Posts and you want to only get the articles that were created since the last time their publication was updated. Now you can do this:
Blog.filter do
having(:posts)
with(:updated_at).lt(:posts => :created_at)
end