Rails，使用named_scope

Question

我需要选择一些从搜索表单提交的动态价格范围。我应该如何使用作用域呢？我正在找这样的东西。

Painting.price_range('1..500'，'2000..5000')

SELECT * FROM paintings WHERE price BETWEEN 1..500 **OR** BETWEEN 2000..5000 etc.

诚挚的问候。Asbjørn Morell

Answer 1

您需要在named_scope上使用lambda。下面的代码应该可以工作：

  named_scope :price_range, lambda { |ranges|
    { 
      :conditions => ["(" + 
         ranges.collect {"price between ? and ?"}.join(" or ") + 
                      ")"] +
         ranges.collect {|r| [r.min, r.max]}.flatten 
    }
  }

第一个ranges.collect创建与您的范围一样多的"between ? and ?“检查，然后第二个ranges.collect展平范围，并将它们作为值添加到条件中。为了安全起见，我在on周围加了括号。

Answer 2

named_scope :price_range, :conditions => ["(price BETWEEN 1 AND 500) OR (price BETWEEN 2000 AND 5000)"]

或

named_scope :price_range, :conditions => ["(price ?) OR (price ?)", (1..500).to_s(:db), (2000..5000).to_s(:db)]

动态

named_scope :price_between, lambda { |from, to| { :conditions => ['price > ? AND price <= ?', from, to] } }

named_scope :price_between, lambda { |from, to| { :conditions => ['price BETWEEN ? AND ?', from, to] } }

->

MyModel.price_between(1,100)