BATCH APEX CLASS SEND ATTACHEMENT FILE TO USER FOR DELETED RECORDS DETAILS.

global class Del_leads implements Database.Batchable<sobject>
{
   public String query;
   public date d=System.today();
   public integer i=7;
   Public Date z=d-i;   
   Public String s;
   public integer j;
   Public string k='Name'+','+'Company'+','+'phone'+','+'Email';
   public datetime m=system.now();
   global Database.QueryLocator start(Database.BatchableContext BC){
      system.debug(query);
      return Database.getQueryLocator(query);   
  }
  Global void execute(Database.BatchableContext BC,List<lead> Lds){   
      for( j=0;j<lds.size();j++){  
         if(j==0){                   
                     s +=k+'\n'+ lds[j].Name+','+lds[j].Company+','+lds[j].phone+','+lds[j].Email;
          } else{                  
                  s +=+'\n'+ lds[j].Name+','+lds[j].Company+','+lds[j].phone+','+lds[j].Email;
         }
     }          
      Blob b=Blob.valueOf(s);
      Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
      efa.setFileName(m+'attachment.csv');
      efa.setBody(b);
      Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
      mail.setToAddresses(new String[] {'youremail@gmail.com'});      
      mail.setSenderDisplayName('Batch Processing');
      mail.setSubject('Batch Process Completed');
      mail.setPlainTextBody('Please find the attachment of deleted records');
      mail.setFileAttachments(new Messaging.EmailFileAttachment[] {efa});   
      Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });     
      delete Lds;         
    }
    global void finish(Database.BatchableContext BC){   
      System.debug(LoggingLevel.WARN,'Deleting Leads Finished');
   }
   
    }

Schedule Class:-
  global class bulkdelleads1 Implements Schedulable{
     global void Execute(SchedulableContext SC){          
        Del_leads ld=new Del_leads();
        ld.query='select id,Name,Company,Phone,Email from
        lead where createddate<=:z and date__c=null limit 200';                
        database.executebatch(ld);          

     }
  }