從ActiveRecord範圍刪除訂單

Question

我正在使用rails ransack（https://github.com/ernie/ransack）允許用戶篩選和排序某些記錄。我使用傳統方法得到過濾和排序的記錄。

@invoices = Invoice.search(params[:q]).result 

現在我想獲得一些概要信息，所以我有

@invoices = Invoice.search(params[:q]).result 
@summary = @invoices.select("sum(balance) as balance_total").first 

除了當用戶指定一個字段進行排序。我收到SQL錯誤：

Column "project_name" is invalid in the ORDER BY clause because 
it is not contained in either an aggregate function or the GROUP BY clause 

我可以從範圍中刪除排序嗎？怎麼樣？

感謝

Answer 1

可以調用reorder方法用一個空字符串。例如： -

[1] pry(main)> Article.order('headline asc').to_sql 
=> "SELECT `articles`.* FROM `articles` ORDER BY headline asc" 
[2] pry(main)> Article.order('headline asc').reorder('').to_sql 
=> "SELECT `articles`.* FROM `articles` " 

Answer 2

您還可以使用unscoped類方法的Rails 3：

class Post < ActiveRecord::Base 
    default_scope :published => true 
end 

posts = Post.all #=> SELECT * FROM posts WHERE published = true 

posts = Post.unscoped do 
    Post.all #=> SELECT * FROM posts 
end 

在Rails 2，它被稱爲with_exclusive_scope。

見https://github.com/rails/rails/commit/bd1666ad1de88598ed6f04ceffb8488a77be4385