Rails ActiveRecord::Relation error

问题

Looking into passing a variable as value on ActiveRcord query key/column?

login = Login.where("email_address" => "geo@bostj.com","active" => 1).select("id")
=> [#<Login id: 767>]
login = Login.where("email_address" => "geo@bostj.com","active" => 1).select("id").class
=> ActiveRecord::Relation

admin = Admin.where("login_id"=>login).exists?

Heeeelp

回答1:

I would do:

login = Login.where(email_address: 'geo@bostj.com', active: 1)
Admin.exists?(login_id: login.pluck(:id))

回答2:

You can write as

login_ids = Login.where("email_address" => "geo@bostj.com","active" => 1).pluck(:id)
Admin.where("login_id in (?)", login_ids).blank?

blank?

Returns true if relation is blank.

Admin.where("login_id in (?)", login_ids) gives back us ActiveRecord::Relation object, so I think we can use #blank? method.

回答3:

It should be

admin = Admin.where("login_id" => login.first.id).exists?

来源：https://stackoverflow.com/questions/23951490/rails-activerecordrelation-error