MySQL横纵表相互转化操作实现方法
(编辑：jimmy 日期: 2024/12/27 浏览：2)
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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希望本文所述对大家MySQL数据库计有所帮助。