合并ActiveRecord_Relation

Question

在模型横幅

中

belongs_to :segment
belongs_to :basic_component
has_many :state_banners, dependent: :destroy
has_many :states, through: :state_banners

scope :banner_have_zero_cities, lambda { includes(state_banners: :state_banner_cities).where(state_banner_cities: {state_banner_id: nil}) }
scope :banner_by_state, lambda { |state_id| where("state_banners.state_id = ?", state_id) }
scope :banner_by_city, lambda { |city_id| joins(state_banners: :state_banner_cities).where("state_banner_cities.city_id = ?", city_id) }

在控制器中

def scoped_collection
   @banners_cities = Banner.banner_by_city(city_id)
   @banners_states =Banner.banner_by_state(city.state_id).banner_have_zero_cities
   @banners = @banners_cities.concat(@banners_states)
   return @banners.joins(:basic_component)
 end

@ banners_states.size =＆GT; 1

@ banners_cities.size =＆GT; 2

@ banners_states.merge（@banners_cities）   SQL（0.2ms）SELECT DISTINCT banners。id FROM banners INNER JOIN state_banners ON state_banners。banner_id = banners。 id内部加入state_banner_cities state_banner_cities。state_banner_id = state_banners。id WHERE（state_banners.state_id = 3）和state_banner_cities 。state_banner_id IS NULL和（state_banner_cities.city_id =＆＃39; 260＆＃39;）LIMIT 25 OFFSET 0 =＆GT; []

我需要3

我尝试concat

@banners = @ banners_cities.concat（@banners_states） @ banners.size =＆gt; 3

但

@ banners.joins（：basic_component）.order（＆＃34; basic_component.order asc＆＃34;）。size =＆gt; 2

CACHE（0.0ms）SELECT COUNT（count_column）FROM（SELECT 1 AS count_column FROM banners INNER JOIN state_banners ON state_banners。banner_id = banners 。id内部加入state_banner_cities state_banner_cities。state_banner_id = state_banners。id内部加入basic_components basic_components 。id = banners。basic_component_id WHERE（state_banner_cities.city_id =＆＃39; 260＆＃39;）LIMIT 25 OFFSET 0）subquery_for_count

:(，帮助

Answer 1

您的帖子有点难以理解，但在查询结束时尝试.limit(3)？