组合搜索范围时出错

Question

我有一个网络服务，它允许客户搜索带有查询参数的文章。如果只包含一个参数，它可以正常工作，但如果我结合search_query 和category，它会失败。这基于找到for_category 的Comfortable_Mexican_Sofa。即使我删除 order 语句，我也会收到此错误。

错误

PG::InvalidColumnReference: 错误: for SELECT DISTINCT, ORDER BY 表达式必须出现在选择列表第 1 行中： ...ms_categories"."label" = '公司新闻' ORDER BY pg_search_... ^ : SELECT DISTINCT "comfy_cms_pages".* FROM "comfy_cms_pages" INNER JOIN “comfy_cms_categorizations”开 "comfy_cms_categorizations"."categorized_id" = "comfy_cms_pages"."id" AND "comfy_cms_categorizations"."categorized_type" = $1 INNER JOIN “comfy_cms_categories”开启“comfy_cms_categories”。“id”= "comfy_cms_categorizations"."category_id" INNER JOIN (SELECT "comfy_cms_pages"."id" AS pg_search_id, (ts_rank((to_tsvector('简单', 合并（“comfy_cms_pages”。“内容缓存”：：文本，''））|| to_tsvector('simple', coalesce("comfy_cms_pages"."label"::text, ''))), (to_tsquery('simple', ''' ' || 'austin' || ' ''' || ':')), 0)) AS 排名 FROM "comfy_cms_pages" WHERE (((to_tsvector('simple', 合并（“comfy_cms_pages”。“内容缓存”：：文本，''））|| 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" = '公司 由 pg_search_comfy_cms_pages.rank DESC 排序的新闻， "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

更新错误

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

工作解决方案，但不是范围，必须小心调用它的顺序

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

Answer 1

我认为最好覆盖您的 CMS 的 for_category 内置过滤器。该查询中的联接太多。

像这样覆盖for_category：

scope :for_category, lambda { |*categories|
  if (categories = [categories].flatten.compact).present?
    self_ids = "{connection.quote_table_name(self.table_name)}.#{connection.quote_column_name(self.primary_key)}"
    self.where(
      "EXISTS (" +
        Comfy::Cms::Categorization.select('1').
          where(categorized_type: self.name).
          where('categorized_id' => self_ids).
          where(category_id: Comfy::Cms::Category.where(label: categories).pluck(:id)).to_sql +
      ")"
    )
  end
}

有关 Rails 中 SQL EXISTS 用法的更多信息，请参阅我的 Rails: SQL EXISTS brief how-to。

您可以在question and answer here 中阅读更多关于您遇到该错误的原因。

具体来说，pg_search 想要按排名对您的结果进行排序。而for_category 只想选择文章的不同字段，而不关心搜索排名。将其代码更改为使用简单的EXISTS 而不是复杂的JOIN 查询将解决这个问题。

Answer 2

我能够通过将reorder 应用于 pg_search 结果的结果来解决这个问题。

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

我也覆盖了 for_category （不需要）

article.rb

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