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MySQL如何实现横纵表相互转化

发表于:2024-11-11 作者:千家信息网编辑
千家信息网最后更新 2024年11月11日,这篇文章主要讲解了MySQL如何实现横纵表相互转化,内容清晰明了,对此有兴趣的小伙伴可以学习一下,相信大家阅读完之后会有帮助。本文实例讲述了MySQL横纵表相互转化操作实现方法。分享给大家供大家参考,
千家信息网最后更新 2024年11月11日MySQL如何实现横纵表相互转化

这篇文章主要讲解了MySQL如何实现横纵表相互转化,内容清晰明了,对此有兴趣的小伙伴可以学习一下,相信大家阅读完之后会有帮助。

本文实例讲述了MySQL横纵表相互转化操作实现方法。分享给大家供大家参考,具体如下:

先创建一个成绩表(纵表)

create table user_score(  name varchar(20),  subjects varchar(20),  score int);insert into user_score(name,subjects,score) values('张三','语文',60);insert into user_score(name,subjects,score) values('张三','数学',70);insert into user_score(name,subjects,score) values('张三','英语',80);insert into user_score(name,subjects,score) values('李四','语文',90);insert into user_score(name,subjects,score) values('李四','数学',100);

再创建一个成绩表(横表)

create table user_score2(  name varchar(20),  yuwen int,  shuxue int,  yingyu int);insert into user_score2(name,yuwen,shuxue,yingyu) values('张三',60,70,80);insert into user_score2(name,yuwen,shuxue,yingyu) values('李四',90,100,0);

纵表转横表

select name,sum(case subjects when '语文' then score else 0 end) as '语文',sum(case subjects when '数学' then score else 0 end) as '数学', sum(case subjects when '英语' then score else 0 end) as '英语'from user_score group by name;

纵表转横表

SELECT  name,'yuwen'  AS   subjects,yuwen  AS  score  FROM  user_score2  UNION  ALL  SELECT  name,'shuxue'  AS   subjects,shuxue  AS  score  FROM  user_score2 UNION  ALL  SELECT  name,'yingyu'  AS   subjects,yingyu  AS  score  FROM  user_score2 ORDER BY name,subjects DESC; 

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