MySQL横纵表相互转化操作实现方法

(编辑：jimmy 日期: 2024/11/26 浏览：3 次 )

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;

更多关于MySQL相关内容感兴趣的读者可查看本站专题：《MySQL查询技巧大全》、《MySQL事务操作技巧汇总》、《MySQL存储过程技巧大全》、《MySQL数据库锁相关技巧汇总》及《MySQL常用函数大汇总》

希望本文所述对大家MySQL数据库计有所帮助。

上一篇：centos7下安装mysql6初始化安装密码的方法
下一篇：关于MYSQL 你需要知道的数据类型和操作数据表