CODEWITHSUNDEEP
ruby-on-railsactiverecordhas-and-belongs-to-many
MindaRyn _
MindaRyn _

Reputation: 43

Rails active record, how can I query in HABTM relation

I have 2 Model which have HABTM relation

User

has_and_belongs_to_many :rooms

Room

has_and_belongs_to_many :users

I also create the migration to join the table like this

create_join_table :users, :rooms do |t|
      t.index [:user_id, :room_id]
      t.index [:room_id, :user_id]
end

I would like to query the room which is contained user_id of user B in among of user A's rooms. How can I do it?

Upvotes: 4

Views: 786

Answers (2)

danielricecodes
danielricecodes

Reputation: 3586

I’m not sure you can do this in a single SQL call but it sounds like you want the union of two sets. 

UserA.rooms & UserB.rooms

That should give you the rooms both users shared.

Upvotes: 2

lacostenycoder
lacostenycoder

Reputation: 11216

this should work

user_b = User.find(id: 123) #or id of user b
user_a = User.find(id: 234) #or id of user a

user_b.rooms.joins(:users).where(users: {id: user_a.id})

Upvotes: 0

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