Question

I have the following “Registration” table :

A player can Join multiple Match (like in the picture, player #12 joined the match #59).

Now I would like to show all players who have registered to the same games as current_player.

So I though I had to :

1. Catch all match_id where player_id = current_player
2. Catch all the players in each match.

Is it the good way ? Or should I know something magic ? How can I do that ?
Thanks for your help.

UPDATE

I tried this :

@matchs_du_joueur = Registrations.where(:player_id => current_user.id)  

@joueurs = Player.joins(:registrations).where(:registrations => { :match_id => @matchs_du_joueur.match_id })

And I have this error :

undefined method `match_id' for #<ActiveRecord::Relation:0x6d8a3b0>

However, I have defined all the has_many_and_belongs_to .
Don’t know how to do.

Answer 1

Yep, that’s it. I’m assuming

class Match < ActiveRecord::Base
  has_many :registrations
  has_many :players, through: :registrations
end

class Player < ActiveRecord::Base
  has_many :registrations
  has_many :matches, through: :registrations
end

class Registration < ActiveRecord::Base
  belongs_to :match
  belongs_to :player
end

then you can just use the following to get all the players that the current_player has matches with

Player.joins(:registrations).where(registrations: { match_id: current_player.match_ids })