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。

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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);

MySQL如何实现横纵表相互转化

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);

MySQL如何实现横纵表相互转化

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;

MySQL如何实现横纵表相互转化

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; 

MySQL如何实现横纵表相互转化

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