问题
I have a Product & Price models, where:
class Product < AR::Base
has_many :prices # there are several types of prices, e.g. for guests, users et.c.
I want to index and sort products by price values, belonging to this product and exact price_type.
ThinkingSphinx::Index.define :product, with: :active_record do
indexes name
indexes k1c
indexes catalogue_code
indexes created_at, sortable: true
indexes prices(:value), as: :price, sortable: true # TODO
has :category_id
has :brand_id
has :kind_cd
has :price_id
end
After rake ts:rebuild I get that
rake aborted!
NoMethodError: undefined method `type' for nil:NilClass
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/attribute/type.rb:64:in `type_from_database'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/attribute/type.rb:17:in `type'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/attribute.rb:4:in `type'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/attribute/sphinx_presenter.rb:30:in `sphinx_type'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/attribute/sphinx_presenter.rb:18:in `collection_type'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/sql_source.rb:96:in `block in append_presenter_to_attribute_array'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/sql_source.rb:93:in `each'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/sql_source.rb:93:in `append_presenter_to_attribute_array'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/sql_source.rb:132:in `prepare_for_render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/active_record/sql_source.rb:65:in `render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration/index.rb:29:in `block in render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration/index.rb:29:in `collect'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration/index.rb:29:in `render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/core/index.rb:53:in `render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration.rb:41:in `block in render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration.rb:41:in `collect'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/riddle-1.5.10/lib/riddle/configuration.rb:41:in `render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/configuration.rb:88:in `render'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/configuration.rb:94:in `block in render_to_file'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/configuration.rb:94:in `render_to_file'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/rake_interface.rb:13:in `configure'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/rake_interface.rb:24:in `index'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/gems/thinking-sphinx-3.1.0/lib/thinking_sphinx/tasks.rb:9:in `block (2 levels) in <top (required)>'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/bin/ruby_executable_hooks:15:in `eval'
/home/asiniy/.rvm/gems/ruby-2.1.0@zhivojoffice/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => ts:rebuild => ts:index
Need I write a raw SQL query or there is another method?
UPD
Analogue sql query for get a one price (after that I want to order by price):
SELECT "prices".* FROM "prices" WHERE "prices"."product_id" = $1 AND "prices"."price_type_id" = 1 LIMIT 1
My prices model. Quantity of price_types are about 5 and changes very seldom.
class Price < ActiveRecord::Base
validates :price_type, :value, :product, presence: true
validates :price_type, uniqueness: { scope: :product }
validates :value, numericality: { greater_than: 0.0 }
belongs_to :price_type
belongs_to :product
end
回答1:
There's a couple of things to note here.
Firstly: attributes are a better fit for sorting (they're sortable by their very nature)... but yes, if you want to sort by the minimum price, then you're going to need a SQL snippet for that:
has 'MIN(prices.value)', as: :price, type: :float
You will also need to ensure you're referring to the prices association either in a separate field or attribute, or explicitly in a call to join, to ensure the table is actually part of the joins in the generated SQL query:
join prices
However, the error you're seeing is unrelated to this - it's complaining that it can't determine the type of an attribute because the specified column doesn't exist. I'm pretty certain this is from your price_id attribute, which should probably go through the prices association:
has prices.id, as: :price_ids
Making this change has the added bonus of ensuring the SQL join exists for the prices table, and so you don't need the join prices line in your index definition.
来源：https://stackoverflow.com/questions/23152124/thinking-sphinx-index-minimum