SQL query to find users that don't have any subscription to a specified list (many-to-many)

Having two tables, "users" and "lists", and a many-to-many "subscriptions" table relating users to lists (thus having foreign keys user_id and list_id), what would be a single SQL query to find all the users that don't have any subscription with a specific list_id (naturally including the use开发者_如何学运维rs that have no subscriptions at all)?

Time to break out not exists again:

select
  u.user_id
from
  users u
where
  not exists (
    select 1 from subscriptions s where s.user_id = u.user_id and s.list_id = N
  )

I used NOT IN and it works well:

SELECT Count(*)
FROM   "users"
WHERE  "users"."id" NOT IN (SELECT "users"."id"
                            FROM   "users"
                                   INNER JOIN "unsubscribes"
                                           ON "unsubscribes"."user_id" =
                                              "users"."id"
                            WHERE  "unsubscribes"."list" = $1) 

Ruby on Rails scopes as a bonus:

  scope :unsubscribed, -> (list) { joins(:unsubscribes).where(unsubscribes: { list: list }) }
  scope :subscribed, -> (list) { where.not(id: User.unsubscribed(list)) }