添加参数为ON子句包括左任何可能的方式连接在轨道上？ [英] Any possible way to add parameters to ON clause on include left joins on rails?

问题描述

我有一个庞大的复杂的查询是这样的：

I have a huge complex query like this:

@objects = Object.joins({ x: :y }).includes(
  [:s, { x: { y: :z } }, { l: :m },:q, :w,
    { important_thing: 
      [:h, :v, :c,:l, :b, { :k [:u, :a] }]  
    }
  ]).where(conditions).order("x.foo, x.bar")

然后我想告诉所有的对象只有 Important_things 创建的两个日期之间。

Then i want to show all Objects and only Important_things that were created at between two dates.

如果我把这个有其中，条款我没有得到所有对象，只有对象，有 Important_things 知情日期之间。

If i put this on there where clause i dont get all Objects, only Objects that has Important_things between informed dates.

使用原始SQL中的解决办法是这样的：

A solution using raw sql was this:

SELECT *从对象左连接上important_things.object_id = objets.id之间'x'和important_things.created_at important_things'Y'

相反的：

SELECT *从对象左连接important_things上important_things.object_id = objets.id那里的important_things.created_at'X'和'Y'

我真的需要所有这些对象，我不希望在关联使用原始SQL，任何解决方法或一种可能性，参数传递给 ON 条款？

I really need all those objects and i don't want to use a raw SQL, any workaround or a possibility to pass parameters to the ON clause on an association?

推荐答案

我做了一个丑陋的解决方法：

I did a ugly workaround:

class Parent < ActiveRecord::Base
  cattr_accessor :dt_begin, dt_end
  has_many :children, conditions: Proc.new { { created_at: (@@dt_begin..@@dt_end) } }
end

class MetasController < ApplicationController
  def index
    Parent.dt_begin = Date.parse(param[:dt_begin])
    Parent.dt_end = Date.parse(param[:dt_end])

    @parents = Parent.includes(:children).where("children.age = ?", params[:age])
  end
end

于是就这样我得到的所有家长即使我没有孩子 created_at这些指定日期之间。

So this way i get all Parents even if i dont have Children created_at between those specified dates.

和它的最重要的部分，我有ActiveRecord的内部的所有对象。

And the most important part of it i have all objects inside the ActiveRecord.

但要小心，因为我没有搞砸cattr_accessor所以我必须设置每次在我搜索家长。

But be careful because i did messed with cattr_accessor so i have to set everytime before i search for Parents.

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