堂综合练习题答案PPT课件

-,第三章综合练习,设有三个关系：S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher)试用SQL语句表示下列查询语句,10、求LIU老师所授课程的每门课程的平均成绩11、检索姓名以L打头的所有学生的姓名和年龄。12、求年龄大于所有女同学年龄的男学生姓名和年龄。13、往关系C中插一个课程元组（C8,VC+,BAO）14、把选修LIU老师课程的女同学选课元组全部删去。15、把低于所有课程总平均成绩的男同学成绩提高5%.,9、统计每门课程的学生选修人数（超过10人的课程才统计）。要求显示课程号和人数，查询结果按人数降序排列，若人数相同，按课程号升序排列。,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),1、查询LIU老师所授课程的课程号和课程名,方法一：Selectcno,cnamefromCwhereteacher=LIU,涉及到的表：C(cno,cname,teacher),方法二：LIKESelectcno,cnamefromCwhereteacherlikeLIU,方法三：INSelectcno,cnamefromCwhereteacherin(LIU),-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsno,snamefromSwhereage23andsex=M,涉及到的表：S(sno,sname,sex,age),方法一：一般的查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsno,snamefromSwhereage23andsnoin(selectsnofromswheresex=男),涉及到的表：S(sno,sname,sex,age),方法二：用IN嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsno,snamefromSwhereage23andsno=ANY(selectsnofromswheresex=男),涉及到的表：S(sno,sname,sex,age),方法三：用=ANY嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsx.sno,sx.snamefromssx,sxywheresx.sno=sy.snoandsx.age23andsy.sex=男,涉及到的表：Sx(sno,sname,sex,age),方法四：自连接,涉及到的表：Sy(sno,sname,sex,age),-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsx.sno,sx.snamefromssxinnerjoinsxyonsx.sno=sy.snowheresx.age23andsy.sex=男,涉及到的表：Sx(sno,sname,sex,age),方法五：内连接,涉及到的表：Sy(sno,sname,sex,age),-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsx.sno,sx.snamefromssxwheresx.age23andexists(select*fromssywheresy.sex=男andsy.sno=sx.sno),涉及到的表：S(sno,sname,sex,age),方法六：用EXISTS嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),2、查询年龄大于23岁的男学生的学号和姓名,Selectsno,snamefromSwhereage23IntersectSelectsno,snamefromSwheresex=男,涉及到的表：S(sno,sname,sex,age),方法七：集合查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),3、查询学号为S3学生所学课程的课程名与任课教师名,Selectcname,teacherfromSC,CwhereSC.cno=C.cnoandsno=S3,涉及到的表：SC(sno,cno,grade)C(cno,cname,teacher),方法一：自然连接查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),3、查询学号为S3学生所学课程的课程名与任课教师名,Selectcname,teacherFromSCinnerjoinCOnSC.cno=C.cnowheresno=S3,涉及到的表：SC(sno,cno,grade)C(cno,cname,teacher),方法二：内连接查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),3、查询学号为S3学生所学课程的课程名与任课教师名,Selectcname,teacherfromCwherecnoin(selectcnofromSCwheresno=S3),涉及到的表：SC(sno,cno,grade)C(cno,cname,teacher),方法三：IN嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),3、查询学号为S3学生所学课程的课程名与任课教师名,Selectcname,teacherfromCwherecno=ANY(selectcnofromSCwheresno=S3),涉及到的表：SC(sno,cno,grade)C(cno,cname,teacher),方法四：=ANY嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),3、查询学号为S3学生所学课程的课程名与任课教师名,Selectcname,teacherfromCwhereexists(select*fromSCwheresno=S3andSC.cno=C.cno),涉及到的表：SC(sno,cno,grade)C(cno,cname,teacher),方法五：EXIST嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,4、查询至少选修LIU老师所授课程中一门课程的女学生姓名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnamefromS,SC,CwhereS.sno=SC.snoandSC.cno=C.cnoandsex=Fandteacher=LIU,方法一：自然连接查询,涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,4、查询至少选修LIU老师所授课程中一门课程的女学生姓名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnamefromSinnerjoinSCOnS.sno=SC.snoinnerjoinConSC.cno=C.cnowheresex=Fandteacher=LIU,方法二：内连接查询,涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,4、查询至少选修LIU老师所授课程中一门课程的女学生姓名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnamefromSwheresex=Fandsnoin(selectsnofromSCwherecnoin(selectcnofromCwhereteacher=LIU),方法三：IN嵌套查询,涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,4、查询至少选修LIU老师所授课程中一门课程的女学生姓名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnamefromSwheresex=FandsnoANY(selectsnofromSCwherecno=ANY(selectcnofromCwhereteacher=LIU),方法四：ANY嵌套查询,涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,4、查询至少选修LIU老师所授课程中一门课程的女学生姓名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnamefromSwheresex=Fandexists(select*fromCwhereteacher=LIUandexists(select*fromSCwhereSC.sno=S.snoandSC.cno=C.cno),方法五：EXISTS嵌套查询,涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),5、查询WANG同学不学的课程的课程号,SelectcnofromCwherenotexists(select*fromSwheresname=WANGandexistsselect*fromSCwheresno=SC.snoandcno=C.cno),涉及到全部的表：S，SC，C,方法一：NOTEXISTS嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),5、查询WANG同学不学的课程的课程号,SelectcnofromCWherecnonotin(selectcnofromSCwheresnoin(selectsnofromSwheresname=WANG),涉及到全部的表：S，SC，C,方法二：NOTIN嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),5、查询WANG同学不学的课程的课程号,SelectcnofromCWherecnoall(SelectcnofromSCwheresno=any(selectsnofromSwheresname=WANG),涉及到全部的表：S，SC，C,方法三：ANY/ALL查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),5、查询WANG同学不学的课程的课程号,SelectcnofromCMinusSelectdistinctcnofromS,SCwhereS.sno=SC.snoandsname=WANG,涉及到全部的表：S，SC，C,方法四：集合查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),5、查询WANG同学不学的课程的课程号,SelectcnofromCwherenotexists(select*fromS,SCwhereS.sno=SC.snoandSC.cno=C.cnoandsname=WANG),涉及到全部的表：S，SC，C,方法五：混合嵌套查询,-,AnIntroductiontoDatabaseSystem,综合练习答案,6、查询至少选修两门课的学生学号,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectsnofromSCgroupbysnohavingcount(*)=2,涉及到的表：SC,-,AnIntroductiontoDatabaseSystem,综合练习答案,7、查询全部学生都选修的课程的课程号与课程名,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),Selectcno,cnamefromCwherenotexists(select*fromSwherenotexists(select*fromSCwheresno=S.snoandcno=C.cno),涉及到全部的表：S，SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,8、查询选修课程包含LIU老师所授全部课程的学生学号,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),SelectdistinctsnofromSCasXwherenotexists(select*fromCwhereteacher=LIUandnotexists(select*fromSCasYwhereY.sno=X.snoandY.cno=C.cno),涉及到的表：SC，C,-,AnIntroductiontoDatabaseSystem,综合练习答案,9、统计每门课程的学生选修人数（超过10人的课程才统计）。要求显示课程号和人数，查询结果按人数降序排列，若人数相同，按课程号升序排列,S(sno,sname,sex,age)SC(sno,cno,grade)C(cno,cname,teacher),Selectcno,count(sno)fromSCgroupbycnohavingcount(*)10orderby2desc,1,涉及到的表：SC,-,AnIntroductiontoDatabaseS