完美的50sql题目及答案.docx

Student(S#,Sname,Sage,Ssex) 学生表 Course(C#,Cname,T#) 课程表 SC(S#,C#,score) 成绩表 Teacher(T#,Tname) 教师表 -查询“1”课程比“2”课程成绩高的所有学生的学号select a.stuid from (select * from t_sc s where s.cid = 1) a, (select * from t_sc s where s.cid = 2) b where a.stuid = b.stuid and a.score b.score;-2、查询平均成绩大于80分的同学的学号和平均成绩；select stuid, avg(score) from t_sc group by stuid having avg(score)80;-3、查询所有同学的学号、姓名、选课数、总成绩；select s.stuid, , c.xks, c.zcj from t_student s left outer join (select stuid, count(cid) xks, sum(score) zcj from t_sc group by stuid) c on s.stuid = c.stuid;select s.stuid, , count(c.cid), sum(c.score) from t_student s left Outer join t_sc c on s.stuid = c.stuid group by s.stuid, ;-4、查询姓“李”的老师的个数；select count(tid) from t_teacher where tname like 李%;-5、查询没学过“叶平”老师课的同学的学号、姓名；select s.stuid, from t_student s, t_course c, t_teacher t, t_sc sc where s.stuid=sc.stuid and c.cid=sc.cid and c.teacherid=t.tid and t.tname!=叶平;-6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；select s.stuid, from t_student s, t_sc c where c.cid=1 and s.stuid=c.stuid and exists (select * from t_sc sc where sc.stuid=s.stuid and sc.cid=2);- select Student.S#,Student.Sname fromStudent,SC where Student.S#=SC.S# andSC.C#=001and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#=002);-7、查询学过“叶平”老师所教的所有课的同学的学号、姓名；select s.sid,s.sname from student s, sc sc where s.sid = sc.sid and sc.cid in(select c.cid from teacher t,course c where t.tid=c.tid and t.tname=叶平)group by s.sid,s.snamehaving count(sc.cid)=(select count(*) from teacher t,course c where t.tid=c.tid and t.tname=叶平);-8、查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名；Select S#, Sname from (select Student.S#, Student.Sname, score, (select score from SC SC_2 where SC_2.S# = Student.S#and SC_2.C# = 002) score2 from Student, SC where Student.S# = SC.S# andC# = 001) S_2 where score2 score; -9、查询所有课程成绩小于60分的同学的学号、姓名；select s.sid,s.sname from student s ,sc c where c.sid=s.sid group by s.sid,s.sname having max(c.score)=60 and s.stuid=sc.stuid);select s.stuid, from t_student s where not exists (select * from t_sc sc where sc.stuid=s.stuid and sc.score=60);-10、查询没有学全所有课的同学的学号、姓名;select s.sid from sc c,course e,student s where c.sid=s.sid and e.cid=c.sid group by s.sid having count(c.cid)(select count(*) from course)select s.stuid, from t_student s,t_sc sc where s.stuid=sc.stuid group by s.stuid, having count(sc.cid) != (select count(cid) from t_course); select Student.S#, Student.Sname from Student, SC whereStudent.S# = SC.S# group by Student.S#, Student.Sname having count(C#) (select count(C#) from Course);-11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名；select distinct s.sid from sc s where s.cid in(select c.cid from sc c where sid=1) and s.sid1select distinct s.stuid, from t_student s, t_sc sc where s.stuid=sc.stuid and s.stuid!=1 and sc.cid in (select cid from t_sc where stuid=1)-select s.stuid, from t_Student s, t_SC sc where s.stuid=SC.Stuid and sc.cid in (select Cid from t_SC where stuid=1);-13、把“t_SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩；update t_sc sc1 set sc1.score = ( select avg(score) from t_sc group by cid having cid in (select cid from t_teacher t, t_course c where t.tid=c.teacherid and t.tname=叶平) and cid=sc1.cid);-14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名；select sid from sc where sid in( select sid from sc group by sid having count(*) =(select count(*) from sc where sid = 1) and cid in (select cid from sc where sid=1); -15、删除学习“叶平”老师课的SC表记录delete t_sc where cid in(select cid from t_course c, t_teacher t where c.teacherid=t.tid and t.tname=Mr.mao);-16、向SC表中插入一些记录，这些记录要求符合以下条件：没有上过编号“5”课程的同学学号、2号课的平均成绩；insert into t_sc select stuid, 5 cid, (select avg(score) from t_sc sc where sc.cid=2) score from t_student s where not exists(select * from t_sc sc where sc.cid=5 and sc.stuid=s.stuid);-17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按-如下形式显示： 学生ID,数据库,企业管理,英语,有效课程数,有效平均分select t.stuid, max(case ame when Chinese then t.score end) Chinese, max(case ame when Math then t.score end) Math, max(case ame when English then t.score end) English, round(avg(t.score), 2) avgscore, count(t.cid) kcs from (select s.stuid, stuname, sc.cid, sc.score, cname from t_student s, t_sc sc, t_course c where s.stuid = sc.stuid and sc.cid = c.cid and in (Chinese, Math, English) t group by t.stuid order by avgscore desc;-18、查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分select cid, max(score) maxscore, min(score) minscore from t_sc group by cid order by cid;-19、按各科平均成绩从低到高和及格率的百分数从高到低顺序select sc.cid, (select name from t_course where cid=sc.cid) cname, round(avg(sc.score),2) avgscore, round(select count(*) from t_sc where cid = sc.cid and score=70)/ (select count(*) from t_sc where cid = sc.cid)*100,2)|% jgl from t_sc sc group by sc.cid order by avgscore, jgl desc;-20、查询如下课程平均成绩和及格率的百分数(用1行显示): -企业管理（001），马克思（002），OO&UML （003），数据库（004） select * from t_sc sc group by sc.cidselect sc.cid, (select name from t_course where cid=sc.cid) cname, case sc.cid when 1 then round(avg(sc.score),2) end chinese_avgscore, case sc.cid when 1 then round(select count(*) from t_sc where cid = sc.cid and score=70)/ (select count(*) from t_sc where cid = sc.cid)*100,2)|% end chinese_jgl from t_sc sc group by sc.cid-21、查询不同老师所教不同课程平均分从高到低显示select sc.cid, round(avg(sc.score),2) avg_score, , t.tname from t_sc sc, t_course c, t_teacher t where sc.cid=c.cid and t.tid=c.teacherid group by sc.cid, , t.tname order by avg_score desc;-22、查询如下语文成绩第 2 名到第 5 名的学生成绩单：-学生ID,学生姓名,语文成绩， 排名select * from (select t.*, rownum tn from (select s.stuid, , min(case when Chinese then sc.score end) chinese_score from t_student s, t_sc sc, t_course c where s.stuid = sc.stuid and sc.cid = c.cid group by s.stuid, order by chinese_score desc) t where rownum 1 -23、统计列印各科成绩,各分数段人数:课程ID,课程名称,100-85,85-70,70-60, =85 and score=70 and score=60 and score70) c,(select count(*) from t_sc where cid=sc.cid and score60) d from t_sc sc, t_course c where sc.cid = c.cid group by sc.cid, ;-24、查询学生平均成绩及其名次 select t.*, rownum rn from (select s.stuid, , avg(sc.score) avg_score from t_student s, t_sc sc where s.stuid=sc.stuidgroup by s.stuid, order by avg_score desc) t;select t.*, row_number() over(order by avg_score desc) pm from (select s.stuid, , avg(sc.score) avg_score from t_student s, t_sc sc where s.stuid=sc.stuidgroup by s.stuid, ) t;-25、查询各科成绩前三名的记录:(不考虑成绩并列情况) select * from (select sc.cid, , sc.score, row_number() over(partition by sc.cid, order by sc.score desc) pmfrom t_sc sc, t_course c where sc.cid=c.cid ) where pm 1;-31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime) select to_char(sysdate,yyyy) year from dual;-32、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列 select cid, round(avg(score),2) avg_score from t_sc group by cid order by avg_score, cid desc;-33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩 select s.stuid, , round(avg(sc.score), 2) avg_score from t_student s, t_sc sc where s.stuid=sc.stuid group by s.stuid, having avg(sc.score)80;-34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数 select s.stuid, stuname, sc.score from t_student s, t_sc sc, t_course c where s.stuid=sc.stuid and sc.cid=c.cid and =Computer and sc.score70;-37、查询不及格的课程，并按课程号从大到小排列 select c.cid, from t_sc sc, t_course c where sc.cid=c.cid group by c.cid,,sc.score having sc.score80;-39、求选了课程的学生人数select count(*) rs from (select stuid from t_sc group by stuid);-40、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩 select s.stuid, stuname, t.max_score from t_student s, t_sc sc,(select c.cid, max(sc.score) max_score from t_sc sc, t_course c, t_teacher t where sc.cid=c.cid and c.teacherid=t.tidand t.tname=Mr.mao group by c.cid) t where s.stuid=sc.stuid and sc.cid=t.cid and sc.score=t.max_score;-41、查询各个课程及相应的选修人数select cid, count(*) rs from t_sc group by cid order by cid;-42、查询不同课程成绩相同的学生的学号、课程号、学生成绩 select * from t_sc sc where exists (select * from t_sc where stuid!=sc.stuid and cid!=sc.cid and score=sc.score);select distinct A.Stuid,B.score from t_SC A ,t_SC B where A.Score=B.Score and A.Cid B.Cid ; -43、查询每门功成绩最好的前两名 select * from (select stuid, cid ,score, row_number() over(partition by cid order by score desc) pm from t_sc) where pm 5 order by rs desc, cid;-45、检索至少选修两门课程的学生学号 select stuid ,count(*) from t_sc group by stuid having count(*) 2;-46、查询全部学生都选修的课程的课程号和课程名 select c.cid, from t_course