mysql动态行转列

DROP TABLE IF EXISTS `score`;
CREATE TABLE `score` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`class` VARCHAR(255) DEFAULT NULL,
`score` DOUBLE DEFAULT NULL,
`userid` INT(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=INNODB AUTO_INCREMENT=8 DEFAULT CHARSET=latin1;

INSERT INTO `score` VALUES ('1', 'math', '90', '1');
INSERT INTO `score` VALUES ('2', 'english', '90', '1');
INSERT INTO `score` VALUES ('3', 'computer', '80', '1');
INSERT INTO `score` VALUES ('4', 'sports', '90', '1');
INSERT INTO `score` VALUES ('5', 'math', '80', '2');
INSERT INTO `score` VALUES ('6', 'english', '85', '2');
INSERT INTO `score` VALUES ('7', 'computer', '100', '2');

SET @EE='';
SET @str_tmp='';
SELECT @EE:=CONCAT(@EE,'SUM(IF(class=\'',class,'\'',',score,0)) AS ',class,',') AS aa
INTO @str_tmp FROM (SELECT DISTINCT class FROM score) A ORDER BY LENGTH(aa) DESC LIMIT 1;

SET @QQ=CONCAT('SELECT ifnull(score.userid,\'total\'),',LEFT(@str_tmp,CHAR_LENGTH(@str_tmp)-1),'  ,SUM(score) AS TOTAL FROM score GROUP BY userid WITH ROLLUP');
PREPARE stmt  FROM @QQ;
EXECUTE stmt ;
DEALLOCATE PREPARE stmt;