Mysql数据库外键设置和查询

SELECT * FROM t_stu s , t_course c ,t_stu_course sc WHERE s.sid = sc.sid AND c.cid = sc.cid;

SELECT s.sname,c.cname FROM t_stu s , t_course c ,t_stu_course sc WHERE s.sid = sc.sid AND c.cid = sc.cid;