用于共同好友的Rails SQL查询
我的用于共同好友的Rails SQL查询,sql,ruby-on-rails,Sql,Ruby On Rails,我的用户型号如下: has_many :relationships, foreign_key: "follower_id", dependent: :destroy has_many :followed_users, through: :relationships, source: :followed has_many :reverse_relationships, foreign_key: "followed_id", cla
用户
型号如下:
has_many :relationships, foreign_key: "follower_id", dependent: :destroy
has_many :followed_users, through: :relationships, source: :followed
has_many :reverse_relationships, foreign_key: "followed_id",
class_name: "Relationship",
dependent: :destroy
has_many :followers, through: :reverse_relationships, source: :follower
我想要的是原始SQL查询,以获取给定用户跟踪并返回的用户
目前,我只获得了以下用户的ID:
followed_user_ids = "SELECT followed_id FROM relationships
WHERE follower_id = #{user.id}"
我有一个返回共同好友的rails方法,但我想要SQL等价物:
def mutual_friends
# interesect both arrays to find similar elements
self.followed_users & self.followers
end
像这样的东西应该有用
SELECT followed_id
FROM relationships
WHERE follower_id = #{user.id} AND followed_id IN (
SELECT follower_id FROM relationships WHERE followed_id = #{user.id}
)
请像这样使用它,让我知道它是否适合你
has_many :company_friendships, autosave: true
has_many :company_friends, through: :company_friendships, autosave: true
has_many :inverse_company_friendships, class_name: "CompanyFriendship", foreign_key: "company_friend_id", autosave: true
has_many :inverse_company_friends, through: :inverse_company_friendships, source: :company, autosave: true
def mutual_company_friends
Company.where(id: (company_friends | inverse_company_friends).map(&:id))
end