global class CampaignSendMailSchedule implements Schedulable {

    global void execute(SchedulableContext SC) {
        Id execBTId = Database.executeBatch(new CampaignSendMailBatch(), 1);
        execBTId = Database.executeBatch(new CampaignSendMailBatch(true), 1);
         execBTId = Database.executeBatch(new CampaignSendMailBatch('1'), 1);
    }
}