SELECT 
  Day, 
  month, 
  year,
  GROUP_CONCAT(total), 
  GROUP_CONCAT(SP_ID)
FROM
(
    SELECT 
      DATE_FORMAT(l.act_date, '%d') AS DAY, 
      DATE_FORMAT(l.act_date, '%M') AS MONTH,
      EXTRACT(YEAR FROM l.act_date) AS YEAR, 
      COUNT(*) as total,l.sp_id 
    FROM lead_activity2 as l
    right outer join salesperson as s on l.sp_id=s.sp_id
    WHERE l.act_name='scb' 
      AND ((l.act_date>='2012-09-07 13:03:27' ) 
      AND (l.act_date<= '2012-11-07 13:03:27')) 
    GROUP BY MONTH, YEAR, DAY, l.sp_id 
    ORDER BY YEAR DESC, MONTH DESC, DAY DESC, l.sp_id DESC
) t GROUP BY day, month, year
http://sqlfiddle.com/#!2/1514d/3 - スキームとクエリを表示できます。
私が手に入れたいのは
18 | october | 2012 | 0,0,1,1 | 6,5,4,3
spid 6 と spid 5 には 10 月 18 日のデータはありませんが、右結合と右外部結合の両方を試してみると、どちらもうまくいかないようです...