AggregateResult throws error: System.ListException: Row with null Id at index: 0

Question

I have this Apex SOQL query:

Map<Id, AggregateResult> results = new Map<Id, AggregateResult>([
    select accountid id, min(id), min(Partner_Admin_Sequence_Number__c) Integer 
    from Contact
    where AccountId IN:deactconacctSet and Contact_Status__c ='Active' and (Partner_Admin_Sequence_Number__c !=null and Partner_Admin_Sequence_Number__c!=0)  group by accountid
    ]);

Answer 1

If your deactconacctSet includes a null then accountId (and so its alias idused in the Map constructor) could be null. Add an additional AccountId != null to avoid that:

Map<Id, AggregateResult> results = new Map<Id, AggregateResult>([
    select accountid id, min(id), min(Partner_Admin_Sequence_Number__c) Integer 
    from Contact
    where AccountId IN:deactconacctSet
    and AccountId != null
    and Contact_Status__c ='Active'
    and (Partner_Admin_Sequence_Number__c !=null and Partner_Admin_Sequence_Number__c!=0)  
    group by accountid
]);