如何计算用户在我的特定项目上完成的所有喜好（Rails）(How to count all the likes that User has done on my specific items (Rails))

 我对这个新手问题表示歉意，我对Rails和SQL比较陌生。 我正在尝试计算用户对我的特定项目所做的所有喜好。 在SO社区和Treehouse Coding的帮助下，我能够显示哪些用户喜欢我的特定项目。 另外，我能够研究如何在我的控制器中使用.join显示我收到的所有喜好（来自Lisa，James，Harry等）。 现在我想显示每个特定用户的计数。 所以举个例子，如果詹姆斯喜欢我的4个项目，我想在詹姆斯旁边展示4个项目。 我在下面列出了我所有的相关代码，非常感谢你们！ 
 
 Index.html.erb 
 
My Fans - <%= @likersnumero%>
<%- @likers.each do |liker| %>
<%= image_tag liker.avatar, width: 25, class: "css-style"  %>
<%= liker.username %>
<% end %>
 
 Items_controller 
 
def index
@items = Item.order("created_at DESC")
if current_user.present? 
@likers = current_user.items.map(&:likes).flatten.map(&:user).flatten
@likersnumero = current_user.items.joins(:likes).map(&:user).count
end
end
 
 item.rb的 
 
class Item < ApplicationRecord
has_many :likes, :counter_cache => true
end
 
 users.rb的 
 
class User < ApplicationRecord
has_many :likes
def likes?(post)
    post.likes.where(user_id: id).any?
end

#Tried using def total_likes in my index.html.erb using <%= liker.total_likes%>
but got the following
 error SQLite3::SQLException: no such column: likes:
 SELECT SUM(likes) FROM "likes" WHERE "likes"."user_id" = ?"
def total_likes
    likes.sum(:likes)   
end
end
 
 的routes.rb 
 
Rails.application.routes.draw do
resources :items do
resource :like, module: :items
end
root to: "items#index"
end
 
 Schema.rb 
 
create_table "items", force: :cascade do |t|
t.string   "product"
t.integer  "user_id"
t.integer  "item_id"
t.datetime "created_at",                      null: false
t.datetime "updated_at",                      null: false
t.string   "avatar_file_name"
t.string   "avatar_content_type"
t.integer  "avatar_file_size"
t.datetime "avatar_updated_at"
t.integer  "likes_count",         default: 0, null: false
end

create_table "likes", force: :cascade do |t|
t.integer  "user_id"
t.integer  "item_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end

My apologies for the newbie question, I'm relatively new to Rails and SQL. I'm trying to count all the likes a User has done on my specific items. With the help of the SO community and from Treehouse Coding I am able to show which Users have liked my specific items. In addition, I was able to research how to show all the likes that I have received (from Lisa, James, Harry, etc.) using .join in my controller. Now I would like to show the count for each specific User. So for instance if James like 4 of my items I would like to show 4 next to James. I have listed all my relevant code below, thank you guys so much!!
 
Index.html.erb
 
My Fans - <%= @likersnumero%>
<%- @likers.each do |liker| %>
<%= image_tag liker.avatar, width: 25, class: "css-style"  %>
<%= liker.username %>
<% end %>
 
Items_controller
 
def index
@items = Item.order("created_at DESC")
if current_user.present? 
@likers = current_user.items.map(&:likes).flatten.map(&:user).flatten
@likersnumero = current_user.items.joins(:likes).map(&:user).count
end
end
 
Item.rb
 
class Item < ApplicationRecord
has_many :likes, :counter_cache => true
end
 
Users.rb
 
class User < ApplicationRecord
has_many :likes
def likes?(post)
    post.likes.where(user_id: id).any?
end

#Tried using def total_likes in my index.html.erb using <%= liker.total_likes%>
but got the following
 error SQLite3::SQLException: no such column: likes:
 SELECT SUM(likes) FROM "likes" WHERE "likes"."user_id" = ?"
def total_likes
    likes.sum(:likes)   
end
end
 
Routes.rb
 
Rails.application.routes.draw do
resources :items do
resource :like, module: :items
end
root to: "items#index"
end
 
Schema.rb
 
create_table "items", force: :cascade do |t|
t.string   "product"
t.integer  "user_id"
t.integer  "item_id"
t.datetime "created_at",                      null: false
t.datetime "updated_at",                      null: false
t.string   "avatar_file_name"
t.string   "avatar_content_type"
t.integer  "avatar_file_size"
t.datetime "avatar_updated_at"
t.integer  "likes_count",         default: 0, null: false
end

create_table "likes", force: :cascade do |t|
t.integer  "user_id"
t.integer  "item_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end

原文：https://stackoverflow.com/questions/41325401