Error when combining search scopes

Question

I have a web-service that allows clients to search for articles with query parameters.It works fine if only one parameter is included but fails if I combine search_query and category. This is based on Comfortable_Mexican_Sofa where for_category is found. Even if I remove the order statement i get this error.

error

PG::InvalidColumnReference: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list LINE 1: ...ms_categories"."label" = 'Company News' ORDER BY pg_search_... ^ : SELECT DISTINCT "comfy_cms_pages".* FROM "comfy_cms_pages" INNER JOIN "comfy_cms_categorizations" ON "comfy_cms_categorizations"."categorized_id" = "comfy_cms_pages"."id" AND "comfy_cms_categorizations"."categorized_type" = $1 INNER JOIN "comfy_cms_categories" ON "comfy_cms_categories"."id" = "comfy_cms_categorizations"."category_id" INNER JOIN (SELECT "comfy_cms_pages"."id" AS pg_search_id, (ts_rank((to_tsvector('simple', coalesce("comfy_cms_pages"."content_cache"::text, '')) || to_tsvector('simple', coalesce("comfy_cms_pages"."label"::text, ''))), (to_tsquery('simple', ''' ' || 'austin' || ' ''' || ':')), 0)) AS rank FROM "comfy_cms_pages" WHERE (((to_tsvector('simple', coalesce("comfy_cms_pages"."content_cache"::text, '')) || to_tsvector('simple', coalesce("comfy_cms_pages"."label"::text, ''))) @@ (to_tsquery('simple', ''' ' || 'austin' || ' ''' || ':'))))) pg_search_comfy_cms_pages ON "comfy_cms_pages"."id" = pg_search_comfy_cms_pages.pg_search_id WHERE (layout_id = '1' AND is_published = 't') AND "comfy_cms_categories"."label" = 'Company News' ORDER BY pg_search_comfy_cms_pages.rank DESC, "comfy_cms_pages"."id" ASC, "comfy_cms_pages"."created_at" DESC

app/models/article.rb

class Article < Comfy::Cms::Page
  cms_is_categorized
  include PgSearch


  pg_search_scope :search_by_keywords, against: [:content_cache, :label], using: { tsearch: { any_word: true, prefix: true } }

app/commands/search_articles_command.rb

class SearchArticlesCommand
  def initialize(params = {})
    @since = params[:since_date]
    @keys = params[:search_query]
    @category = params[:category]
  end

  def execute
    Article.unscoped do
      query = if @since.present?
                Article.article.since_date(@since)
              else
                Article.published_article
              end
      query = query.for_category(@category) if @category.present?
      query = query.search_by_keywords(@keys) if @keys.present?
      query.where('').order(created_at: :desc)
    end
  end
end

comfortable-mexican-sofa/lib/comfortable_mexican_sofa/extensions/is_categorized.rb

module ComfortableMexicanSofa::IsCategorized

  def self.included(base)
    base.send :extend, ClassMethods
  end

  module ClassMethods
    def cms_is_categorized
      include ComfortableMexicanSofa::IsCategorized::InstanceMethods

      has_many :categorizations,
        :as         => :categorized,
        :class_name => 'Comfy::Cms::Categorization',
        :dependent  => :destroy
      has_many :categories,
        :through    => :categorizations,
        :class_name => 'Comfy::Cms::Category'

      attr_accessor :category_ids

      after_save :sync_categories

      scope :for_category, lambda { |*categories|
        if (categories = [categories].flatten.compact).present?
          self.distinct.
            joins(:categorizations => :category).
            where('comfy_cms_categories.label' => categories)
        end
      }
    end
  end

  module InstanceMethods
    def sync_categories
      (self.category_ids || {}).each do |category_id, flag|
        case flag.to_i
        when 1
          if category = Comfy::Cms::Category.find_by_id(category_id)
            category.categorizations.create(:categorized => self)
          end
        when 0
          self.categorizations.where(:category_id => category_id).destroy_all
        end
      end
    end
  end
end

ActiveRecord::Base.send :include, ComfortableMexicanSofa::IsCategorized

Updated Error

PG::SyntaxError: ERROR:  syntax error at or near "."
LINE 4: ...e = 'Class' AND categorized_id = 'comfy_cms_pages'.'id' AND ...
                                                             ^
: SELECT "comfy_cms_pages".* FROM "comfy_cms_pages" INNER JOIN (SELECT "comfy_cms_pages"."id" AS pg_search_id, (ts_rank((to_tsvector('simple', coalesce("comfy_cms_pages"."content_cache"::text, '')) || to_tsvector('simple', coalesce("comfy_cms_pages"."label"::text, ''))), (to_tsquery('simple', ''' ' || 'austin' || ' ''' || ':*')), 0)) AS rank FROM "comfy_cms_pages" WHERE (((to_tsvector('simple', coalesce("comfy_cms_pages"."content_cache"::text, '')) || to_tsvector('simple', coalesce("comfy_cms_pages"."label"::text, ''))) @@ (to_tsquery('simple', ''' ' || 'austin' || ' ''' || ':*'))))) pg_search_comfy_cms_pages ON "comfy_cms_pages"."id" = pg_search_comfy_cms_pages.pg_search_id WHERE "comfy_cms_pages"."layout_id" = $1 AND "comfy_cms_pages"."is_published" = $2 AND (
        EXISTS (
          SELECT 1 FROM categorizations
          WHERE categorized_type = 'Class' AND categorized_id = 'comfy_cms_pages'.'id' AND category_id IN (2)
        ))  ORDER BY pg_search_comfy_cms_pages.rank DESC, "comfy_cms_pages"."id" ASC

working solution but not a scope and have to be careful of order its being called

  def self.for_category(_category)
    Comfy::Cms::Categorization.includes(:category).references(:category).select(:categorized).pluck(:categorized_id)
    find(ids)
  end

Answer 1

I was able to solve this problem by applying reorder to the result of the pg_search result.

search_command.rb

class SearchArticlesCommand
  def initialize(params = {})
    @since = params['since_date']
    @keys = params['search_query']
    @category = params['category']
  end

  def execute
    Article.unscoped do
      query = Article.article
      query = if @since.present?
                query.since_date(@since)
              else
                query.published
              end
      query = query.for_category(@category) if @category.present?
      query = query.search_by_keywords(@keys).reorder('updated_at DESC') if @keys.present?
      query
    end
  end
end

I also overrode for_category (not required)

article.rb

  scope :for_category, (lambda do |category|
    published
      .joins(:categories)
      .group(:id)
      .where('comfy_cms_categories.label' => category)
      .select('comfy_cms_pages.*')
  end)