MySQL行转列与列转行

行转列

例如：把图1转换成图2结果展示

图1 

 

图2

 

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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;

 

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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：

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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

图3

 

列转行SQL：

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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】