Question

我正在使用Rails 2.3，我有3个表，用于管理建筑物的用户权限。 mygroups表是用户和建筑物所属的组列表。 mygroupsbuildings是具有相关组的建筑物列表。 mygroupsusers是具有关联组的用户列表。

create_table "mygroups", :force => true do |t|
  t.string   "name"
  t.integer  "user_id"
  t.string   "user_name"
  t.integer  "permissions"
end

create_table "mygroupbuildings", :force => true do |t|
  t.integer  "mygroup_id"
  t.integer  "building_id"
end

create_table "mygroupusers", :force => true do |t|
  t.integer  "mygroup_id"
  t.integer  "user_id"
  t.string   "user_name"
end

我想创建一个查询，查明特定的user_id是否是与特定building_id相同的组的成员。

我已设置以下关联：

class Mygroup < ActiveRecord::Base  
  has_many   :mygroupusers
  has_many   :mygroupbuildings
end

class Mygroubuilding < ActiveRecord::Base  
  belongs_to :mygroup
  has_many   :mygroupusers, :through => :mygroup
end

class Mygroupuser < ActiveRecord::Base
  belongs_to :mygroup
  has_many   :mygroupbuildings, :through => :mygroup
end

我写了以下查询：

Mygroupuser.find(:all,
                 :include => :mygroupbuildings,
                 :select => "mygroupbuildings.building_id, mygroupusers.user_id",
                 :conditions => ["mygroupbuildings.building_id = '#{building.id}' AND mygroupusers.user_id = '#{current_user.user_id}'"])

这给我以下错误：

ActiveRecord :: StatementInvalid（Mysql ::错误：'on子句'中的未知列'mygroups.mygroup_id'：SELECT mygroupusers。id AS t0_r0，mygroupusers。{{1 AS t0_r1，mygroup_id。mygroupusers AS t0_r2，user_id。mygroupusers AS t0_r3，user_name。mygroupusers AS t0_r4，{{1 } {。{1}} AS t0_r5，created_at。mygroupusers AS t1_r0，updated_at。mygroupbuildings AS t1_r1，id。mygroupbuildings AS t1_r2，mygroup_id。mygroupbuildings AS t1_r3，coursewalk_id。mygroupbuildings AS t1_r4 FROM created_at LEFT OUTER JOIN mygroupbuildings ON（{{1} }。updated_at = mygroupusers。mygroups）LEFT OUTER JOIN mygroupusers ON（id。mygroups = mygroup_id。{{ 1}}）WHERE（mygroupbuildings.building_id ='2'和mygroupusers.user_id = '55'））：

谢谢，

尼克，

Answer 1

这是查询需要如何设置以返回包含查询的user_id和building_id的组：

Mygroup.find(:all,
             :include => [:mygroupbuildings, :mygroupusers],
             :conditions => ["mygroupbuildings.building_id = #{building.id} AND mygroupusers.user_id = #{current_user.user_id}"])

Rails has_many＆amp;通过查询

1 个答案: