Update sibling records from the same object fails

Question

I have a custom object called 'myObject__c'. This object has a lookup with Account. Now I want to get the values of an existing record (e.g. recordA) and update another record (e.g. recordB).

this is my code:

List<myObject__c> abc = new List<myObject__c>();
    
List<myObject__c> record1 = [SELECT field1, field2 FROM myObject__c WHERE AccountID = 1];
    
List<myObject__c> record2 = [SELECT field1, field2 FROM myObject__c WHERE AccountID = 2];
    
for (myObject__c oldrecord : record1) {
     for(myObject__c newrecord : record2) {
          newrecord.field1 = oldrecord.field1;
          newrecord.field2 = oldrecord.field2;
      }
}
 
update newrecord;

when I try to save the file, it gives me an error:

Variable does not exist: newrecord // last line

Answer 1

A List<MyObject__c> does not have properties of the fields on those records within. You have to index in to get a single record. Alternatively, if you know you will get exactly one result, just assign to a single record.

MyObject__c record1 = [...];
MyObject__c record2 = [...];
record2.Field__c = record1.Field__c;