Question

我正在为我的应用程序中的“玩家”做一个过滤器部分..

我此时按“位置”过滤，但我需要在数据库中过滤“birthday.year”生日已完成1900-00-00

我以前做过很好的研究，但我可以“混合”或“结合”我的参数...我找到的最佳答案就在这里（所以它不是重复的） Rails: combining optional params into a query

我是Rails中的菜鸟，所以我会感谢任何帮助我只是做一个设计的整合..

这是我的代码，但我如何使用minyear和maxyear按位置和年龄进行过滤，例如..

谢谢！

def index
    @candidates = Player.order("created_at DESC")

    position = params[:position]
    minyear = params[:minyear]
    maxyear = params[:maxyear]


    if position == 'goalkeeper'
  @candidates = @candidates.where(position:'goalkeeper') 
 elsif position == 'cedefense'
  @candidates = @candidates.where(position:'cedefense') 
 elsif position == 'ridefense'
  @candidates = @candidates.where(position:'ridefense') 
 elsif position == 'ledefense'
  @candidates = @candidates.where(position:'ledefense') 
 elsif position == 'defmedium'
  @candidates = @candidates.where(position:'defmedium') 
 elsif position == 'ofemedium'
  @candidates = @candidates.where(position:'ofemedium') 
 elsif position == 'rimedium'
  @candidates = @candidates.where(position:'rimedium') 
 elsif position == 'lemedium'
  @candidates = @candidates.where(position:'lemedium') 
 elsif position == 'offensive'
  @candidates = @candidates.where(position:'offensive') 
 elsif position == 'scoach'
  @candidates = @candidates.where(position:'scoach') 
 elsif position == 'sprepf'
  @candidates = @candidates.where(position:'sprepf')                 
 else
  @candidates = Player.all
 end

经过大量研究后，我想出了这个

 position = params[:position]
    minyear = params[:minyear]
    maxyear = params[:maxyear]

  if  params[:position].nil? 
  @candidates = Player.all
  elsif  !params[:position].nil? && params[:minyear].nil?
  @candidates = @candidates.where("position = ?", position) 
  elsif !params[:minyear].nil?
  @candidates = @candidates.where("position = ? and birthday = ?", position, minyear )                 
 else
  @candidates = Player.all
 end

现在唯一的问题是，我之前说过的生日有一个完整的格式，我只对这一年感兴趣......我怎么能解决这个问题？

提前致谢

没关系，它可以像这样工作

@candidates = @candidates.where("position = ? and birthday < ?", position, minyear )

感谢Alex D我现在就这样，

@candidates = Player.scoped # for Rails 3
 if params[:position].present?
   @candidates = @candidates.where(position: position)
 end


 if year = params[:year]
   date = Date.new(year)
   # this will find all people whose birthday is within the given year
   # using YEAR(birthday) will likely cause a full table scan;
   #   it's better to use a range query
   @candidates = @candidates.where("birthday >= ? AND birthday <= ?", Date.new(minyear), Date.new(maxyear).end_of_year)
 end

Answer 1

首先，如果您知道Active Record的where和其他类似方法是可链接的，您可以改进代码：

 @candidates = Player.order('created_at DESC')
 # if you don't want to set a default order, you can use Player.scoped in Rails 3
 # I forget what it is for Rails 4. Maybe just Player.all.
 # In Rails 3, .all returns an Array, which doesn't allow you to chain additional
 #   where conditions, etc.
 if params[:position].present?
   @candidates = @candidates.where(position: position)
 end
 if params[:minyear].present?
   @candidates = @candidates.where(birthday: minyear)
 end

现在第二部分：你真的想在生日那一年匹配。有几种方法可以做到这一点，但如果您有正确的索引，这可以从数据库索引中受益：

 if year = params[:year]
   date = Date.new(year)
   # this will find all people whose birthday is within the given year
   # using YEAR(birthday) will likely cause a full table scan;
   #   it's better to use a range query
   @candidates = @candidates.where("birthday >= ? AND birthday <= ?", date, date.end_of_year)
 end

由于你的param被称为minyear，我猜你实际上可能想要所有生日都在给定年份或更晚的人。在那种情况下：

 @candidates = @candidates.where("birthday >= ?", Date.new(year))

或者如果它是minyear和maxyear：

 @candidates = @candidates.where("birthday >= ? AND birthday <= ?", Date.new(minyear), Date.new(maxyear).end_of_year)

Answer 2

@candidates = @candidates.where("position = ? and year(birthday) < ?", position, minyear )

尝试一下，这将符合您的目的。

结合Rails中的参数

2 个答案: