Mysql related query

rubyonrails-talk
1

Hello Friends,

I have a rails application where requirement is that, I want to display books based on likes and expiry date…

I am using the following query

“select books., (select count() from likes where likes.book_id = books.id) as ct from books, book_expires where book_expires.book_id = books.id order by ct ASC, book_expires.end_at DESC”

And the output I am getting is on the bases of count not end_date…

Please let me know where I am getting wrong thanks…

Thanks abhis

2

Hello

First of all, if there are 2 models … then i think you got it wrong … assuming you have

class Book < ActiveRecord::Base

has_many :likes

has_one :book_expire

end

class BookExpire < ActiveRecord::Base

belongs_to :book

end

class Like < ActiveRecord::Base

belongs_to :book

end

Then you could add " , :counter_cache => true " to the belongs_to association (if needed add a likes_count field in the Book table)

if you do that …, then you could do a very easy query like

@books = Book.joins(:book_expire).all.order(’ likes_count ASC, book_expires.end_at DESC’) # and i would add a limit ()

have a look here : http://railscasts.com/episodes/23-counter-cache-column (even the move uses rails 2.x … the concept and syntax is still valid )

Alecslupu

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