MySQL行转列与列转行

时间:2021-06-03 15:01:33

行转列

例如:把图1转换成图2结果展示

MySQL行转列与列转行

图1

MySQL行转列与列转行

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 '',
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_grade
GROUP BY USER_NAME;

列转行

例如:把图1转换成图3结果展示

MySQL行转列与列转行

图3

列转行SQL:

select user_name, '语文' COURSE , CN_SCORE as SCORE from test_tb_grade2
union select user_name, '数学' COURSE, MATH_SCORE as SCORE from test_tb_grade2
union select user_name, '英语' COURSE, EN_SCORE as SCORE from test_tb_grade2
order by user_name,COURSE;

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