mysql分组分页

DELIMITER $$

USE `ltpdb`$$

DROP PROCEDURE IF EXISTS `file_noteid_page`$$

CREATE DEFINER=`root`@`%` PROCEDURE `file_noteid_page`(i_noteid VARCHAR(64),
  i_cid VARCHAR(64),
  i_type VARCHAR(64),
  i_userid  VARCHAR(64),
  i_page_num INT,
  i_page_size INT)
BEGIN
DECLARE v_start_index INT ;
DECLARE v_end_index INT ;
DECLARE v_count INT;
SET v_start_index= (i_page_num-1)*i_page_size;
SET v_end_index = i_page_num*i_page_size;
SELECT COUNT(*) INTO v_count FROM (
SELECT  noteid FROM lc_file WHERE
noteid IS NOT NULL
AND  ((i_cid IS NULL && cid IS NULL ) OR cid = i_cid)
AND (i_userid IS NULL OR usrid = i_userid)
AND (i_type IS NULL OR (i_type='4' &&  aclock IS NOT NULL )  OR (i_type IN('1','2','3')  && ftype=i_type  ))
AND (i_noteid IS NULL OR noteid=i_noteid )  GROUP BY noteid ORDER BY cversion DESC ) a;
SET @rw=0;
  SELECT  al.noteid ,v_count AS total,rn FROM (
SELECT (@rw := @rw + 1) AS rn ,b.noteid FROM ( SELECT noteid FROM lc_file WHERE
noteid IS NOT NULL
AND  ((i_cid IS NULL && cid IS NULL ) OR cid = i_cid)
AND (i_userid IS NULL OR usrid = i_userid)
AND (i_type IS NULL OR (i_type='4' &&  aclock IS NOT NULL )  OR (i_type IN('1','2','3')  && ftype=i_type  ))
AND (i_noteid IS NULL OR noteid=i_noteid )  GROUP BY noteid  ORDER BY cversion DESC) b ) al
    WHERE rn > v_start_index AND  rn <= v_end_index;
END$$

DELIMITER ;

-- ( SELECT noteid FROM lc_file WHERE
noteid IS NOT NULL
AND  ((i_cid IS NULL && cid IS NULL ) OR cid = i_cid)
AND (i_userid IS NULL OR usrid = i_userid)
AND (i_type IS NULL OR (i_type='4' &&  aclock IS NOT NULL )  OR (i_type IN('1','2','3')  && ftype=i_type  ))
AND (i_noteid IS NULL OR noteid=i_noteid )  GROUP BY noteid  ORDER BY cversion DESC)

如果不套一层(select noteid)rn顺序就会乱。