Ruby on Rails，通过两个条件查找 [英] Ruby on Rails, find by two conditions

问题描述

我有以下模型：


我试图通过两个字段的组合来查找给定模型的所有值。

  create_tableusers，：force => true do | t | 
 t.stringname
 t.stringurl
 t.integerclicks_given
 t.integerclicks_received
 t.datetimecreated_at 
 t.datetimeupdated_at
 end 
  

我定义了这个方法对于模型：

  def credits 
 credits = self.clicks_given  -  self.clicks_received 
 end 
  

我正在尝试查找给定信用点以上的所有用户：

  @users = User.find（：all，：conditions => {credits> =？，-5}）
  

和：

  @users = User .find（：all，：conditions => {clicks_given  -  clicks_received> =？，-5}）
  

失败。为了找到合适的用户，正确的语句应该是什么？

解决方案

传递条件作为数组而不是散列：

  @users = User.find（：all，：conditions => [clicks_given  -  clicks_received> =？， 5]）
  

由于credits不是数据库列，所以第一个版本将不起作用。

编辑：

或者在Rails 3语法中，用你的命令：

  @users = User.where（clicks_given  -  clicks_received> =？，5）.order（clicks_given  -  clicks_received）
  




I am trying to find all values of a given model by a combination of two fields.

I have the following model:

  create_table "users", :force => true do |t|
    t.string   "name"
    t.string   "url"
    t.integer  "clicks_given"
    t.integer  "clicks_received"
    t.datetime "created_at"
    t.datetime "updated_at"
  end

and I have defined this method for the model:

  def credits
    credits = self.clicks_given - self.clicks_received
  end

I am trying to find all users above a given credits:

  @users = User.find(:all, :conditions => { "credits >= ?", -5 })

and:

  @users = User.find(:all, :conditions => { "clicks_given - clicks_received >= ?", -5 })

Fail. What should is the correct statement to to find the right users?

解决方案

Pass the condition as an array instead of a hash:

@users = User.find(:all, :conditions => [ "clicks_given - clicks_received >= ?", -5 ])

The first version will not work since "credits" is not a database column.

EDIT:

Or in Rails 3 syntax, with your order:

@users = User.where("clicks_given - clicks_received >= ?", 5).order("clicks_given - clicks_received")

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