title: Yii2: findone() syntax on multiple where condition
body: <p>I have a table ipd_charges with columns</p>
  
  <p>table - ipd_charges</p>
  
  <pre><code>id    doctor room_category charges_cash charges_cashless
  1        1          1              200            300
  2        1          2              300            400
  </code></pre>
  
  <p>table - patient_admission</p>
  
  <pre><code>id patient_name tpa_name(if not null, equivalent to charges_cashless)
  1        1        Null
  2        2         1
  </code></pre>
  
  <p>table daily_ward_entry</p>
  
  <pre><code>id  patient_name  room_name  doctor_name charges ( from ipd charges)
  1          1           1           1         200
  2          2           2           1         400
  </code></pre>
  
  <p>I am trying to use this query which is failing:</p>
  
  <pre><code>$model = \app\models\IpdCharges::find()
           -&gt;where(['doctor'=&gt;$id])
           -&gt;andwhere(['room_category'=&gt;$this-&gt;room_name])-&gt;one();
  </code></pre>
  
  <p>Thanks. Please tell me if any more info is needed.</p>
  
  <p>A help will be greatly appreciated. </p>