title: Rails Arel - how to do INTERVAL 1 DAY with MySQL
body: <p>In a Rails 4 app using <a href="https://github.com/rails/arel" rel="nofollow">Arel</a>, how would I construct the following part of a <code>WHERE</code> clause?:</p>
  
  <pre><code>stopped_at &lt; DATE_ADD(DATE(started_at), INTERVAL 1 DAY)
  </code></pre>
  
  <p>I have the following already:</p>
  
  <pre><code>started_at_date = Arel::Nodes::NamedFunction.new('DATE', [arel_table[:started_at]])
  next_day = Arel::Nodes::NamedFunction.new('DATE_ADD',
                                            [started_at_date, 'INTERVAL 1 DAY'])
  conditions = arel_table[:stopped_at].lt(next_day)
  </code></pre>
  
  <p>The problem is that INTERVAL 1 DAY gets quoted:</p>
  
  <pre><code>&gt;&gt; conditions.to_sql
  =&gt; "`my_table`.`stopped_at` &lt; DATE_ADD(DATE(`my_table`.`started_at`), 'INTERVAL 1 DAY')"
  </code></pre>
  
  <p>MySQL does not like it being quoted, so I need to tell Arel not to quote it. How do I do this?</p>