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copied!<p><code>Shirt.uniq.pluck(:fabric)</code> returns a <code>Relation</code>. Therefore it will never be <code>nil</code>.</p> <p>This <code>Relation</code> defines parts of a sql query. This says: <em>Give me (all|one of the) unique values of fabric in the database.</em> To actually run that query, you need to call a method on that relation that triggers the database call: <code>all</code>, <code>first</code>, <code>each</code>, <code>any?</code>, <code>blank?</code> ... </p> <p>Through the lack of context, I do not know how you use your <code>Shirt</code> model. But I guess the query will never give you the expected answer. Because <code>Shirt.uniq.pluck(:fabric)</code> will always return something as long there is at least one row in that table. Imagine there is only one row in the table and it's <code>fabric</code> is <code>nil</code>, than <code>Shirt.uniq.pluck(:fabric).blank?</code> would determine <code>Shirt.uniq.pluck(:fabric)</code> to <code>[nil]</code>. And <code>[nil].blank? == false</code></p> <p>If you work on one specific shirt, use <code>@shirt.fabric.present?</code> If you want to know if there is at least one shirt in the db without a fabric <code>Shirt.where(fabric: nil).any?</code></p> <p>I recommend to read:</p> <ul> <li><a href="http://guides.rubyonrails.org/active_record_querying.html" rel="nofollow">http://guides.rubyonrails.org/active_record_querying.html</a></li> <li><a href="http://api.rubyonrails.org/classes/ActiveRecord/Relation.html" rel="nofollow">http://api.rubyonrails.org/classes/ActiveRecord/Relation.html</a></li> </ul>

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