ruby on rails - Bind variables to ActiveRecord select -

in activerecord, how can bind prepared statement variables in select? example:

group.select('(extract(epoch created_at) / $1)::int interval')

the $1 parameter calculated user input tempted concatenate strings, guess it's no ideal. in advance!

you can go around, must define method in model calculations need:

def self.interval_divided_by dividend   group.select('(extract(epoch created_at))::int interval').interval / dividend end

then use it:

group.interval_divided_by 4

Ben