1）根据表查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩 2）根据表查询在SC表存在成绩的学生信息 实验数据： 学生表： createtableStudent( Sidvarchar(6), Snamevarchar(10), Sagedatetime, Ssexvarchar(10)); insertintoStudentvalues('01','赵雷','1990-01-01','男'); insertintoStudentvalues('02','钱电','1990-12-21','男'); insertintoStudentvalues('03','孙风','1990-05-20','男'); insertintoStudentvalues('04','李云','1990-08-06','男'); insertintoStudentvalues('05','周梅','1991-12-01','女'); insertintoStudentvalues('06','吴兰','1992-03-01','女'); insertintoStudentvalues('07','郑竹','1989-07-01','女'); insertintoStudentvalues('08','王菊','1990-01-20','女') 成绩表 createtableSC( Sidvarchar(10), Cidvarchar(10), scoredecimal(18,1)); insertintoSCvalues('01','01',80); insertintoSCvalues('01','02',90); insertintoSCvalues('01','03',99); insertintoSCvalues('02','01',70); insertintoSCvalues('02','02',60); insertintoSCvalues('02','03',80); insertintoSCvalues('03','01',80); insertintoSCvalues('03','02',80); insertintoSCvalues('03','03',80); insertintoSCvalues('04','01',50); insertintoSCvalues('04','02',30); insertintoSCvalues('04','03',20); insertintoSCvalues('05','01',76); insertintoSCvalues('05','02',87); insertintoSCvalues('06','01',31); insertintoSCvalues('06','03',34); insertintoSCvalues('07','02',89); insertintoSCvalues('07','03',98) 课程表 createtableCourse( Cidvarchar(10), Cnamevarchar(10), Tidvarchar(10)); insertintoCoursevalues ('01','语文','02'); insertintoCoursevalues ('02','数学','01'); insertintoCoursevalues ('03','英语','03') 教师表 createtableTeacher( Tidvarchar(10), Tnamevarchar(10)); insertintoTeachervalues ('01','张三'); insertintoTeachervalues ('02','李四'); insertintoTeachervalues ('03','王五')