SELECT s.id, s.name, s.class_id, c.name class_name, s.gender, s.score
FROM students s
RIGHT JOIN classes c ON class_id = c.id
UNION
SELECT s.id, s.name, s.class_id, c.name class_name, s.gender, s.score
FROM classes c
LEFT JOIN students s ON class_id = c.id;
Faded-零
看其他博客了解到,MySQL 不支持全连接,但可以通过左外连接 + UNION + 右外连接实现:
看到评论中也没有具体写出来,我就写出来提供参考