mysql 查询小demo

create table student_one(
	name varchar(50) default ‘‘ not null,
	type varchar(10) not null default 0,
	score float(5,2) not null default 0.00
)Engine=innodb;


create table student_two(
	name varchar(50) default ‘‘ not null,
	math  float(5,2) not null default 0.00,
	english float(5,2) not null default 0.00,
	chinese float(5,2) not null default 0.00
)Engine=innodb;

select a.name,a.score as ‘math‘,b.score as ‘chinese‘,c.score as ‘english‘
from student_one a join student_one b join student_one c 
on a.name=b.name and a.name=c.name and b.name=c.name 
where a.type=‘math‘ and b.type=‘chinese‘ and c.type=‘Engine‘;

select a.name,a.math as score,‘math‘ as type from student_two a 
union
select b.name,b.english as score,‘english‘ as type from student_two b 
union
select c.name,c.chinese as score,‘chinese‘ as type from student_two c;