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POScope with join on :has_many :through association
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  1. POScope with join on :has_many :through association
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    copied!<pre><code>class Users &lt; ActiveRecord::Base has_many :meetings, :through =&gt; :meeting_participations has_many :meeting_participations end class Meetings &lt; ActiveRecord::Base has_many :users, :through =&gt; :meeting_participations has_many :meeting_participations end class MeetingParticipations &lt; ActiveRecord::Base belongs_to :user belongs_to :meeting scope :hidden, where(:hidden =&gt; true) scope :visible, where(:hidden =&gt; false) end </code></pre> <p><code>hidden</code> is an extra boolean column within the m2m association table. Given some <code>Users</code> instance <code>current_user</code>, I want to do</p> <pre><code>current_user.meetings.visible </code></pre> <p>which will retrieve a collection of <code>Meetings</code> for which the user is a participant where the <code>hidden</code> column is <code>false</code>. The closest I have gotten is adding the following scope to the <code>Meetings</code> class</p> <pre><code>scope :visible, joins(:meeting_participations) &amp; MeetingParticipation.visible </code></pre> <p>The <code>scope</code> does filter the <code>Meetings</code> against the <code>MeetingParticipations</code> table, however there is no join/condition against the <code>MeetingParticipations</code> table related to <code>current_user</code>.</p> <p>The issue with this is, if <code>current_user</code> and <code>another_user</code> are both participants for some <code>Meetings</code> instance, a <code>Meetings</code> record in the result set will be returned for each participant that has <code>hidden</code> set to <code>false</code>. If <code>current_user</code> has <code>true</code> set for <code>hidden</code> for all <code>Meetings</code>, if <code>another_user</code> is a participant in any of those same Meetings with <code>hidden</code> set to <code>false</code>, those <code>Meetings</code> will appear in the <code>Meetings.visible</code> result set.</p> <p>Is it possible to have a scope as I've mentioned above which will properly join on the <code>User</code> instance? If not, can someone recommend a solution to this?</p>
 

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