Question

• I have a Deal model and one Category model having many to many mapping (has_many:through, as i m saving some related data too.)

• Also I have a city model which is also having many to many mapping with deal model (Again has_many through)

• Category model has no relationship with City model.

Now to search deals based upon keywords (Keywords means, i have indexed some columns like title of the deal, description etc)

 @deals = Deal.search(params[:keywords],:per_page => 20, :page => params[:page])

Question is:

Now I need to group these deals based upon the categories, basically first category has 4 deals, second category has 7 deals and so on provided city_id is given.

 @deals = @city.deals.search(params[:keywords],:per_page => 20, :page => params[:page])

PS:
You can think of something like this:
End user will enter Select London as a location and then enter “fun” as a keyword and then i need to search the database to check the london deals having having “fun” keyword and group them based upon the various categories.
I hope i am able to explain the question.

EDIT

Some issues with indexing:
rake thinking_sphinx:rebuild –trace
** Invoke thinking_sphinx:rebuild (first_time)
** Invoke thinking_sphinx:app_env (first_time)
** Execute thinking_sphinx:app_env
** Execute thinking_sphinx:rebuild
** Invoke thinking_sphinx:index (first_time)
** Invoke thinking_sphinx:app_env
** Execute thinking_sphinx:index
Generating Configuration to /Users/me/projects/deals/config/development.sphinx.conf
rake aborted!

Cannot automatically map attribute category_ids in Deal to an
equivalent Sphinx type (integer, float, boolean, datetime, string as ordinal).
You could try to explicitly convert the column's value in your define_index
block:
  has "CAST(column AS INT)", :type => :integer, :as => :column
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/attribute.rb:334:in `translated_type_from_database'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/attribute.rb:170:in `type'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/attribute.rb:139:in `include_as_association?'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/attribute.rb:107:in `to_select_sql'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source/sql.rb:69:in `block in sql_select_clause'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source/sql.rb:69:in `collect'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source/sql.rb:69:in `sql_select_clause'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source/sql.rb:19:in `to_sql'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source.rb:117:in `set_source_sql'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/source.rb:51:in `to_riddle_for_core'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/index.rb:114:in `block in to_riddle_for_core'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/index.rb:113:in `each'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/index.rb:113:in `each_with_index'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/index.rb:113:in `to_riddle_for_core'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/index.rb:83:in `to_riddle'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/active_record.rb:245:in `block in to_riddle'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/active_record.rb:244:in `collect'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/active_record.rb:244:in `to_riddle'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/configuration.rb:164:in `block in generate'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/configuration.rb:161:in `each'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/configuration.rb:161:in `generate'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/configuration.rb:177:in `build'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/tasks.rb:78:in `block (2 levels) in <top (required)>'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:205:in `call'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:200:in `each'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/me/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke'
/Users/me/.rvm/gems/ruby-1.9.2-p290/gems/thinking-sphinx-2.0.5/lib/thinking_sphinx/tasks.rb:95:in `block (2 levels) in <top (required)>'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:205:in `call'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:200:in `each'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/me/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:112:in `invoke_task'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:90:in `block (2 levels) in top_level'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:90:in `each'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:90:in `block in top_level'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:84:in `top_level'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:62:in `block in run'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/lib/rake/application.rb:59:in `run'
/Users/me/.rvm/gems/ruby-1.9.2-p290@global/gems/rake-0.9.2/bin/rake:32:in `<top (required)>'
/Users/me/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `load'
/Users/me/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `<main>'
Tasks: TOP => thinking_sphinx:index

Answer 1

I supposed that you have a Deal model like

class Deal < ActiveRecord::Base
  has_many :category_deals
  has_many :categories, :through => :category_deals
  has_many :city_deals
  has_many :cities, :through => :city_deals

  define_index do
    indexes :name
    has category_deals.category_id, :as => :category_ids
    has city_deals.city_id, :as => :city_ids
  end
end

So you want to search by city and given category or categories (1,3,2) for the given city with categories ASC order:

Deal.search(params[:keywords], :with => {:category_ids => [1,3,2], :city_ids => params[:city_id]}, :order => "category_ids ASC", :per_page => 20, :page => params[:page])