How do I mass update existing records with a Field value where the field value is Blank? Need a code to be executed in the Execute Anonymous window

Question

How do I mass update existing records with a field where the value is blank? I need code to be executed in the Execute Anonymous window.

Field name is Owner__c Object name is Account__c

I am using the below query to pull the data. Now I need to overwrite the blank fields in the records.

SELECT Id, Name, Owner__c, Originator__c FROM Account__c WHERE Owner__c = ''

Answer 1

You can use following code

List<Account> listAccount = [
    SELECT Id, Name, Owner__c, Originator__c
    FROM Account__c WHERE Owner__c = ''
    LIMIT 10000
];

for(Account__c acc : listAccount)
{
  acc. Owner__c = 'YOUR NEW VALUE'
}

update listAccount;