如果你想使用数组作为参数，下面的代码在Rails 4中工作:

query = Order.where(uuid: uuids, id: ids)
Order.where(query.where_values.map(&:to_sql).join(" OR "))
#=> Order Load (0.7ms)  SELECT "orders".* FROM "orders" WHERE ("orders"."uuid" IN ('5459eed8350e1b472bfee48375034103', '21313213jkads', '43ujrefdk2384us') OR "orders"."id" IN (2, 3, 4))

更多信息:在Rails 4中使用数组作为参数的OR查询。

如果你想在一个列的值上使用OR操作符，你可以传递一个数组到.where, ActiveRecord将使用IN(value,other_value):

Model.where(:column => ["value", "other_value"]

输出:

SELECT `table_name`.* FROM `table_name` WHERE `table_name`.`column` IN ('value', 'other_value')

这应该在单个列上实现与OR相同的效果

Rails 5附带了一个or方法。(链接到文档)

该方法接受ActiveRecord::Relation对象。例如:

User.where(first_name: 'James').or(User.where(last_name: 'Scott'))

使用activerecord_any_of gem，您可以编写

Book.where.any_of(Book.where(:author => 'Poe'), Book.where(:author => 'Hemingway')

rails + arel，一个更清晰的方式:

# Table name: messages
#
# sender_id:    integer
# recipient_id: integer
# content:      text

class Message < ActiveRecord::Base
  scope :by_participant, ->(user_id) do
    left  = arel_table[:sender_id].eq(user_id)
    right = arel_table[:recipient_id].eq(user_id)

    where(Arel::Nodes::Or.new(left, right))
  end
end

生产:

$ Message.by_participant(User.first.id).to_sql 
=> SELECT `messages`.* 
     FROM `messages` 
    WHERE `messages`.`sender_id` = 1 
       OR `messages`.`recipient_id` = 1

MetaWhere插件非常棒。

轻松混合OR's和and 's，任何关联的连接条件，甚至指定OUTER join 's!

Post.where({sharing_level: Post::Sharing[:everyone]} | ({sharing_level: Post::Sharing[:friends]} & {user: {followers: current_user} }).joins(:user.outer => :followers.outer}