MySQL横纵表相互转化操作实现方法
编程学习 2021-07-05 14:37www.dzhlxh.cn编程入门
这篇文章主要介绍了MySQL横纵表相互转化操作,结合实例形式分析了MySQL横纵表相互转化操作基本原理、实现方法与相关注意事项,需要的朋友可以参考下
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：《》、《》、《》、《》及《》
希望本文所述对大家MySQL数据库计有所帮助。