对于教学数据库的3个基表(S表示学生表,C表示课程表,SC表示学生选课表...答:1.create table S (SNO char(10) primary key,SNAME varchar(20),AGE int,SEX char(2)default '男')2.SELECT CNO,CNAME FROM C WHERE TEACHER='LI'3.insert into C values('C01','高等数学','LI')4.SELECT SNO,SNAME FROM S WHERE AGE>21 AND SEX='男'5.select CNAME,TEACHER FROM ...