rails sort_by方法的下降和偏移量限制

Question

i just wondering do offset limit and ordering by descending in my custom method rails after i called sort_by total_like method. this is my custom method in model

 class Post < ApplicationRecord
 def total_like
    self.likeposts.count
 end
 ... more code ...

and this is script when i tried to calling post that sort by total_like in descending

    if POST==@current_entity
            @entities=[]
            @entity.where(paramshash).sort_by(&:total_like).reverse!.each.with_index do |entity, index|
              if index >= params[:offset].to_i && index <= params[:offset].to_i + params[:limit].to_i
                @entities << entity
              end
            end
    render json: @entities

can anyone make it simply and does'nt need to call all the record in my Post table :(

Answer 1

I think something like this might work:

Post
  .joins(:likeposts)
  .group('posts.id')
  .order('COUNT(likeposts.id) DESC')
  .offset(params[:offset])
  .limit(params[:limit])