Is there a way to resolve Illegal conversion from List<AggregateResult> to List<String> in SForce Apex?

Question

I am tryin gto fetch a field value and below is the code,but i am getting below error in SForce

Illegal conversion from List<AggregateResult> to List<String>


                public class PickListHandler {
                    @AuraEnabled
                    public static List<String> getLevel1(){


                       List<AggregateResult> groupedLevel1
                  = [select Level_1__c,COUNT(id) from Case_Type_Data__c  group by Level_1__c];

                        for(AggregateResult  ar : groupedLevel1){                
                           System.debug('Level Value Is' + ar.get('Level_1__c'));

                        }

                        return groupedLevel1;
                    } 


                }

Can some one help in fixing ?

Thanks in advance

Answer 1

Just change your function's returning type to List<AggregateResult> :

public class PickListHandler {
    @AuraEnabled
    public static List<AggregateResult> getLevel1() {
        List<AggregateResult> groupedLevel1 =
            [SELECT Level_1__c, COUNT(Id) FROM Case_Type_Data__c GROUP BY Level_1__c];
        for(AggregateResult ar : groupedLevel1) {                
            System.debug('Level Value Is' + ar.get('Level_1__c'));
        }
        return groupedLevel1;
    } 
}