sql查询顺序问题
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因此，我在activerecord中有一个跟随模型，我将使用ѭ0来返回最近回复的讨论，但是如何修改私有方法以按最近的回复时间对返回的讨论进行排序？
# Table name: discussions
#
# id :integer not null, primary key
# title :string(255) not null
# content :text(255) not null
# created_at :datetime
# updated_at :datetime
# user_id :integer
# discussable_id :integer
# discussable_type :string(255)
class Discussion < ActiveRecord::Base
has_many :comments, :as => :commentable, :dependent => :destroy
#
#this is the scope that I am having trouble with:
#
scope :user_replied_group_discussions, lambda {|user| replied_by(user) }
private
def self.replied_by(user)
discussion_ids = %(SELECT commentable_id FROM comments
WHERE commentable_type = \'Discussion\' AND user_id = :user_id)
where(\"discussable_type = \'Group\' AND id IN (#{discussion_ids}) \",
{ :user_id => user })
end
end
# Table name: comments
#
# id :integer not null, primary key
# content :text
# created_at :datetime
# updated_at :datetime
# commentable_id :integer
# commentable_type :string(255)
# user_id :integer
#
class Comment < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
belongs_to :user
end
没有找到相关结果
已邀请:
1 个回复
先对冈蒲
时间排序：where(\"discussable_type = \'Group\' AND id IN (#{discussion_ids}) order by updated_at DESC \",SELECT d.* , MAX(c.created_at) AS lastCommentTime FROM discussions d JOIN comments c ON d.id = c.commentable_id WHERE c.commentable_type = \'Discussion\' AND c.user_id = userIDtoCheck GROUP BY d.id ORDER BY lastCommentTime DESC <--- latest first