Hi, I created a VF page where we can search for a case using the case number. 

However, in the result, I also want to display the Open Activites related to the Case.
I am able to reference the Case object fields in the page, but cannot figure out how to do that with the Open Activites fields (Status, Priority, Subject)

Controller:

public class casesearchcontroller {
     public list <case> cas {get;set;}
    public casesearchcontroller(ApexPages.StandardController controller) {
    
    }
    
   public string searchstring {get;set;}  
    
   public void search(){  
     string searchquery='select casenumber,Email__c,Category__c,SubCategory__c,(Select  ActivityDate, Status, Priority,Subject FROM OpenActivities)from case where CaseNumber like \'%'+searchstring+'%\' Limit 30';  
     cas= Database.query(searchquery);  
   }  
   public void clear(){  
   cas.clear();  
   }  
 }


Page:

<apex:page standardController="Case" extensions="caseextension" showheader="false" >
 <apex:form >  
 <apex:inputText value="{!searchstring}" label="Input"/>   
  <apex:commandButton value="Find Case" action="{!search}"/>  
  <apex:commandButton value="Clear Search" action="{!search}"/>  
   <apex:pageBlock title="Search Result">  
    <apex:pageblockTable value="{!cas}" var="c">  
      
     <apex:column value="{!c.CaseNumber}"/>  
     <apex:column value="{!c.Email__c}"/>
      <apex:column value="{!c.Category__c}"/>
    <apex:column value="{!c.SubCategory__c}"/>
    
     
    </apex:pageblocktable>
          </apex:pageBlock> 
     </apex:form> 
</apex:page>

Any help?

Thanks!