50道数据库练习题.docx

50道数据库练习题.docxselect*fromStudent;select*fromCourse;select*fromTeacher;select*fromSC;createtableStudent(S#varchar2(10),Snamevarchar2(10),Sagedate,Ssexvarchar2(10));commit;insertintoStudentvaluesfOl','赵雷',to_date(*1990-01-017yyyy-mm-dd,),男);insertintoStudentvalues(*02','钱电',to_date('1990-12-21'/yyyy-mm-dd'),'男');insertintoStudentvalues('03‘,'孙风',to_date(,1990-05-207yyyy-mm-dd,)「男*);insertintoStudentvaluesC04','李云',to_date(*1990-08-067yyyy-mm-dd'),'男');insertintoStudentvaluesfOS','周梅',to_date(*1991-12-01'/yyyy-mm-dd'),女);insertintoStudentvalues(*06','吴兰',to_date(*1992-03-01','yyyy-mm-dd'),'女');insertintoStudentvalues(*07','郑竹',to_date('1989-07-01'yyyy-mm-dd'),女);insertintoStudentvalues('08‘,'王菊',to_date(*1990-01-20',Vyyy-mm-dd*),'女');commit;createtableCourse(C#varchar2(10),Cnamevarchar2(10),T#varchar2(10));insertintoCoursevalues('O1',语文',*02');insertintoCoursevalues('O2*,'数学',*01');insertintoCoursevalues('O3','英语',*03');createtableTeacher(T#varchar2(10),Tnamevarchar2(10));insertintoTeachervalues('01','张三');insertintoTeachervalues(*02','李四');insertintoTeachervaluesf03',,王五');createtableSC(S#varchar2(10),C#varchar2(10),scorenumber(4,1))insertintoSCvalues('01','0T,80);insertintoSCvalues('01','02',90);insertintoSCvalues('01','03',99);insertintoSCvaluesfOZ,‘01’,70);insertintoSCvaluesfOZ,‘02',60);insertintoSCvalues(*02','03',80);insertintoSCvalues('O3',*01',80);insertintoSCvalues('O3','02',80);insertintoSCvalues('O4','01',50);insertintoSCvalues(,04,,*02*,30);insertintoSCvalues('O4','03',20);insertintoSCvalues('O5','01',76);insertintoSCvalues('O5','02',87);insertintoSCvalues('O6','01',31);insertintoSCvalues('06‘,‘03’,34);insertintoSCvalues(*07',*02',89);insertintoSCvalues(*07','03',98);-K查询”01”课程比”02”课程成绩高的学生的信息及课程分数selecta.*,,,scb,#=####='#='02'>;・・2、查询”0广课程比”02”课程成绩低的学生的信息及课程分数selecta.*,,,scb,#=##=##=,01'#='02'<;・・3、查询平均成绩大于等于60分的同学的学生