行转列

例如：把图1转换成图2结果展示

图1 

 

图2

 

CREATE TABLE `TEST_TB_GRADE` (  `ID` int(10) NOT NULL AUTO_INCREMENT,  `USER_NAME` varchar(20) DEFAULT NULL,  `COURSE` varchar(20) DEFAULT NULL,  `SCORE` float DEFAULT '0',  PRIMARY KEY (`ID`)) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

 

insert into TEST_TB_GRADE(USER_NAME, COURSE, SCORE)  values("张三", "数学", 34),("张三", "语文", 58),("张三", "英语", 58),("李四", "数学", 45),("李四", "语文", 87),("李四", "英语", 45),("王五", "数学", 76),("王五", "语文", 34),("王五", "英语", 89);

　　

行转列SQL：

SELECT user_name ,    MAX(CASE course WHEN '数学' THEN score ELSE 0 END ) 数学,    MAX(CASE course WHEN '语文' THEN score ELSE 0 END ) 语文,    MAX(CASE course WHEN '英语' THEN score ELSE 0 END ) 英语FROM test_tb_gradeGROUP BY USER_NAME;

　　

列转行

例如：把图1转换成图3结果展示

图3

 

列转行SQL：

select user_name, '语文' COURSE , CN_SCORE as SCORE from test_tb_grade2union select user_name, '数学' COURSE, MATH_SCORE as SCORE from test_tb_grade2union select user_name, '英语' COURSE, EN_SCORE as SCORE from test_tb_grade2order by user_name,COURSE;

 

【转载自：http://blog.csdn.net/jx_870915876/article/details/52403472】