Rails: Finding all Users whose relationship has a specified attribute
ruby-on-rails
Solution
You can achivete this by doing the following:
User.includes(:rosterplayers).where(rosterplayers: { pending: true })
This will return all User records having at least 1 `rosterplayer` having `pending` set to `true`.
Limit the query to a specific `roster` instance:
User.includes(:rosterplayers).where(rosterplayers: { pending: true, roster_id: your_roster_id })
# your_roster_id can actually be an array of IDs
Additional note: Be carefull with .joins and .includes:
# consider these models
Post
belongs_to :user
#^^
User
has_many :posts
#^
# the `includes/joins` methods use the name defined in the model :
User.includes(:posts).where(posts: { title: 'Bobby Table' })
#^ ^
# but the `where` uses the pluralized version (table's name) :
Post.includes(:user).where(users: { name: 'Bobby' })
#^^^ ^
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Problem
I have three models: ``` class User < ActiveRecord::Base has_many :rosterplayers has_many :rosters, -> { uniq } , :through => :rosterplayers end class Roster < ActiveRecord::Base has_many :rosterplayers has_many :users, -> { uniq }, through: :rosterplayers end class Rosterplayer < ActiveRecord::Base belongs_to :roster belongs_to :user validates :user_id, :uniqueness => { :scope => :roster_id } end ``` The Rosterplayer table has three columns: `user_id`, `roster_id,` and `pending` (boolean) Question: Given a roster, how would I retrieve all users that are currently pending? Attempt: My first attempt was to loop through all the users in the roster: ``` @team.rosters[0].users.each do |u| Rosterplayer.find_by(roster_id: rosters[0].id, user_id: u.id, pending: true) end ``` But I feel like there is a better way of doing it.