title: Where clause on a Salesforce subquery
body: <p>I'm running into some trouble filtering my SOQL Query by date where the date field belongs to the child of the object I'm querying. </p>
  
  <p>I couldn't find anything in the documentation, and I tried two different queries, both of which failed:</p>
  
  <pre><code>SELECT Name, (SELECT Date__c FROM Child__r) 
  FROM Parent Where Date__c &gt;= &lt;todays_date&gt;
  
  SELECT Name, (SELECT Date__c FROM Child__r) 
  FROM Parent Where Child__r.Date__c &gt;= &lt;todays_date&gt;
  </code></pre>
  
  <p>Is this even possible in Salesforce?</p>