Mysql 多表查询

mysql version: 5.7.*

数据

students

id	name
1001	tom
1002	jack
1003	jason

results

student_id	score	score_name
1001	60	Math
1002	70	History
1005	80	History

内链接

select * from student as s join results as r on s.id=r.student_id where r.score>60;

select * from 表1 join 表2 on 表1.id=表2.id where 其他条件

左链接

left join左边的表中的数据全部查询出来，右边的的表中符合条件的查询出来

select * from student as s left join retults as r on s.id=r.student_id where r.score>60

select * from 表1 right join 表2 on 表1.id=表2.id where 其他条件

右链接

rigit join右边的表中的数据全部查询出来，左边的的表中符合条件的查询出来

select * from student as s right join retults as r on s.id=r.student_id where r.score>60

select * from 表1 left join 表2 on 表1.id=表2.id where 其他条件