Rails ActiveRecord条件

Question

有没有办法创造这样的条件？

@products = Product.find(:all,
  :limit => 5,
  :conditions => { :products => { :locale => 'en', :id NOT '1' }, :tags => { :name => ['a','b']})

我想列出所有产品,不包括产品1. Thx.

Answer 1

Rails 3

使用squeel gem.

Product.where(
  :products => { :locale => 'en', :id.not_in => '1' }, 
  :tags => { :name => ['a','b']}
).limit(5)

Rails 2

为此使用AR Extensions.它支持以下条件修饰符:

* _lt => less than
* _gt => greater than
* _lte => less than or equal to
* _gte => greater than or equal to
* _ne => not equal to
* _not => not equal to

现在,您可以按如下方式重写查询:

@products = Product.find(:all,
  :limit => 5,
  :joins => [:tags],
  :conditions => { :locale => 'en', :id_not => '1', :tags => { :name => ['a','b']}
)

Answer 2

它应该是这样的.原始查询不是很清楚,根据您的需要进行调整.

@products = Product.find(:all,
  :limit => 5,
  :conditions => ["locale = ? AND id <> ? AND tags.name IN (?)", "en", 1, ['a','b'],
  :joins => "tags"
)

Answer 3

另一种方法是使用merge_conditions将哈希条件转换为字符串.然后,您可以添加任何您想要的内容,或者使用其他选项再次调用merge_conditions.

hash_conditions = {:category => 'computers'}
conditions = Product.merge_conditions(hash_conditions) + ' AND products.id NOT IN(1139) '
products = Product.find(:all, :conditions => conditions)