三个数据库
多表连接查询,且去掉重复列,使用 USING()
select * from (select * from school left join course USING (courseid)) e left join student USING (studentid);
扫描二维码关注公众号,回复:
9122870 查看本文章
select * from school left join course USING (courseid)相当于
select * from school left join course on school.courseid=course.courseid;