title: Validation rule formula for empty picklist field
body: <p>I am trying to define a set of actions for a user based on salesforce picklists.</p>
  <p>I have a main field called <code>fHCM2__Reason__c</code> that is a picklist containing multiple absence reason types - Sickness, Annual Leave etc</p>
  <p>I then have a related field called <code>Annual_Leave_includes_a_trip_abroad__c</code> that is a picklist with two possible options - Yes or No</p>
  <p>I want to define that if a user selects &quot;Annual Leave&quot; from the <code>fHCM2__Reason__c</code> picklist they cannot leave the field <code>Annual_Leave_includes_a_trip_abroad__c</code> blank and have to choose Yes or No.</p>
  <p>Currently I have the below:</p>
  <pre><code>ISPICKVAL(fHCM2__Reason__c, &quot;Annual Leave&quot;) 
  &amp;&amp; ISBLANK(Annual_Leave_includes_a_trip_abroad__c) 
  </code></pre>
  <p>My problem with my current method is that because <code>Annual_Leave_includes_a_trip_abroad__c</code> is a picklist, that has &quot;Yes&quot; or &quot;No&quot; options, this is causing an error as I cannot see how to define this in the above <code>PICKVAL()</code> statement.</p>
  <p>Can anyone advise how can I state that if a user choose &quot;Annual Leave&quot; then they have to provide a value (Yes or No) for the <code>Annual_Leave_includes_a_trip_abroad__c</code> field if they choose Annual Leave?</p>