title: Using relational expression in yii findOne()
body: <p>In Yii2, to use <strong>findOne()</strong> to grab a single record with exact match is simple. For example:</p>
  
  <pre><code>// find the first customer whose age is 30 and whose status is 1
  $customer = Customer::findOne(['age' =&gt; 30, 'status' =&gt; 1]);
  </code></pre>
  
  <p>But what if you want to find one where <code>age</code> is <strong>less than</strong> 30?</p>