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POActiveRecord find with association details
 

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    <p>Suppose I am doing matchmaking of users and games. I have models containing users and games. </p> <pre><code>class Game &lt; ActiveRecord::Base has_and_belongs_to_many :users class User &lt; ActiveRecord::Base has_and_belongs_to_many :games </code></pre> <p>Games can have many users, users can be playing many games. Because of HASBM I have a table called games_users too.</p> <p>I want to search and find games that are waiting for players, which do not also contain the username of the player (i.e. I don't want to add the same player to a game twice...)</p> <p>I want something like this:</p> <p>@game = Game.find_by_status(Status::WAITING_USERS, :condition => "game.users.doesnt_contain('username=player')</p> <p>But I'm not sure how to do it?</p> <p><strong>Update:</strong> </p> <p>Using jdl's solution, I got the code to run, but get items that I tried to exclude returned in the results. Here's my test code:</p> <pre><code>logger.debug "Excluding user: #{@user.id}" games = Game.excluding_user(@user) if (games != nil &amp;&amp; games.count &gt; 0) @game = Game.find(games[0].id) games[0].users.each { |u| logger.debug "returned game user: #{u.id}" } end </code></pre> <p>(the above code also begs 2 questions.... - how do I get a result of just one game instead of an array, and how to I get a non-readonly version of it; that's why I do the second Game.find...)</p> <p>And here's the output in the log:</p> <pre><code>Excluding user: 2 Game Load (0.3ms) SELECT `games`.* FROM `games` left outer join games_users gu on gu.game_id = games.id WHERE (gu.game_id is null or gu.user_id != 2) Game Columns (1.0ms) SHOW FIELDS FROM `games` SQL (0.2ms) SELECT count(*) AS count_all FROM `games` left outer join games_users gu on gu.game_id = games.id WHERE (gu.game_id is null or gu.user_id != 2) Game Load (0.1ms) SELECT * FROM `games` WHERE (`games`.`id` = 3) games_users Columns (6.8ms) SHOW FIELDS FROM `games_users` User Load (0.9ms) SELECT * FROM `users` INNER JOIN `games_users` ON `users`.id = `games_users`.user_id WHERE (`games_users`.game_id = 3 ) returned game user: 1 returned game user: 2 </code></pre>
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