postgresql order by field(id)

scratch.rb

# ensures that your models return with the same ordering as ids
#   e.g., [1,2,3] yields [<YourModel id=1>, <YourModel id=2>, <YourModel id=3>]
# via: https://gist.github.com/cpjolicoeur/3590737, brilliant solution
values = ids.each_with_index.map { |id, index| "(#{id}, #{index + 1})" }.join(",")
YourModel.unscoped.where(id: ids).joins("join (VALUES #{values}) as x(id, ordering) ON listings.id = x.id").order("x.ordering")