global class BatchAccountRevenue implements Database.Batchable<sObject>,Schedulable

global Database.QueryLocator start(Database.BatchableContext BC)
{
    String query = 'Select Id, Name,All_Time_Revenue_c  from Account';
    return Database.getQueryLocator(query);
}

global void execute(Database.BatchableContext BC, List<Account> scope)
{
    for(Account a : scope)
    {

   AggregateResult[] agList = [SELECT SUM(Normalized_Amount__c) totalSum FROM Invoice__c where Normalized_Amount__c!= null and Id=:a.id];

   a.All_Time_Revenue_c = (double)agList[0].get('totalSum');
    }
    update scope;
}
global void finish(Database.BatchableContext BC){
}
 global void execute(SchedulableContext sc) {
    BatchAccountRevenue batchable = new BatchAccountRevenue();
    Database.executeBatch(batchable, 300);
}