問題： 1、查詢“001”課程比“002”課程成績高的所有學生的學號; select a.S# from (select s#,score from SC where C#='001') a,(select s#,score from SC where C#='002') b where a.score>b.score and a.s#=b.s#; 2、查詢平均成績大于60分的同學的學號和平均成績; select S#,avg(score) from sc group by S# having avg(score) >60; 3、查詢所有同學的學號、姓名、選課數、總成績; select Student.S#,Student.Sname,count(SC.C#),sum(score) from Student left Outer join SC on Student.S#=SC.S# group by Student.S#,Sname 4、查詢姓“李”的老師的個數; select count(distinct(Tname)) from Teacher where Tname like '李%'; 5、查詢沒學過“葉平”老師課的同學的學號、姓名; select Student.S#,Student.Sname from Student where S# not in (select distinct( SC.S#) from SC,Course,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='葉平'); 6、查詢學過“001”并且也學過編號“002”課程的同學的學號、姓名; select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# and SC.C#='001'and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002'); 7、查詢學過“葉平”老師所教的所有課的同學的學號、姓名; select S#,Sname from Student where S# in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='葉平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='葉平')); 8、查詢課程編號“002”的成績比課程編號“001”課程低的所有同學的學號、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# and C#='001') S_2 where score2 score; 9、查詢所有課程成績小于60分的同學的學號、姓名; select S#,Sname from Student where S# not in (select Student.S# from Student,SC where S.S#=SC.S# and score>60); 10、查詢沒有學全所有課的同學的學號、姓名; select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# group by Student.S#,Student.Sname having count(C#) (select count(C#) from Course); 11、查詢至少有一門課與學號為“1001”的同學所學相同的同學的學號和姓名; select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001'; 12、查詢至少學過學號為“001”同學所有一門課的其他同學學號和姓名; select distinct SC.S#,Sname from Student,SC where Student.S#=SC.S# and C# in (select C# from SC where S#='001'); 13、把“SC”表中“葉平”老師教的課的成績都更改為此課程的平均成績; update SC set score=(select avg(SC_2.score) from SC SC_2 where SC_2.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# and Course.T#=Teacher.T# and Teacher.Tname='葉平'); 14、查詢和“1002”號的同學學習的課程完全相同的其他同學學號和姓名; select S# from SC where C# in (select C# from SC where S#='1002') group by S# having count(*)=(select count(*) from SC where S#='1002'); 15、刪除學習“葉平”老師課的SC表記錄; Delect SC from course ,Teacher where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='葉平'; 16、向SC表中插入一些記錄，這些記錄要求符合以下條件：沒有上過編號“003”課程的同學學號、2、 號課的平均成績; Insert SC select S#,'002',(Select avg(score) from SC where C#='002') from Student where S# not in (Select S# from SC where C#='002'); 17、按平均成績從高到低顯示所有學生的“數據庫”、“企業管理”、“英語”三門的課程成績，按如下形式顯示： 學生ID,,數據庫,企業管理,英語,有效課程數,有效平均分 SELECT S# as 學生ID ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 數據庫 ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企業管理 ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英語 ,COUNT(*) AS 有效課程數, AVG(t.score) AS 平均成績 FROM SC AS t GROUP BY S# ORDER BY avg(t.score) 18、查詢各科成績最高和最低的分：以如下形式顯示：課程ID，最高分，最低分 SELECT L.C# As 課程ID,L.score AS 最高分,R.score AS 最低分 FROM SC L ,SC AS R WHERE L.C# = R.C# and L.score = (SELECT MAX(IL.score) FROM SC AS IL,Student AS IM WHERE L.C# = IL.C# and IM.S#=IL.S# GROUP BY IL.C#) AND R.Score = (SELECT MIN(IR.score) FROM SC AS IR WHERE R.C# = IR.C# GROUP BY IR.C# ); 19、按各科平均成績從低到高和及格率的百分數從高到低順序 SELECT t.C# AS 課程號,max(course.Cname)AS 課程名,isnull(AVG(score),0) AS 平均成績 ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分數 FROM SC T,Course where t.C#=course.C# GROUP BY t.C# ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC 20、查詢如下課程平均成績和及格率的百分數(用"1行"顯示): 企業管理（001），馬克思（002），OOUML （003），數據庫（004） SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企業管理平均分 ,100 * SUM(CASE WHEN C# = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '001' THEN 1 ELSE 0 END) AS 企業管理及格百分數 ,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 馬克思平均分 ,100 * SUM(CASE WHEN C# = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '002' THEN 1 ELSE 0 END) AS 馬克思及格百分數 ,SUM(CASE WHEN C# = '003' THEN score ELSE 0 END)/SUM(CASE C# WHEN '003' THEN 1 ELSE 0 END) AS UML平均分 ,100 * SUM(CASE WHEN C# = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) AS UML及格百分數 ,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 數據庫平均分 ,100 * SUM(CASE WHEN C# = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '004' THEN 1 ELSE 0 END) AS 數據庫及格百分數 FROM SC 21、查詢不同老師所教不同課程平均分從高到低顯示 SELECT max(Z.T#) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.C# AS 課程ＩＤ,MAX(C.Cname) AS 課程名稱,AVG(Score) AS 平均成績 FROM SC AS T,Course AS C ,Teacher AS Z where T.C#=C.C# and C.T#=Z.T# GROUP BY C.C# ORDER BY AVG(Score) DESC 22、查詢如下課程成績第 3 名到第 6 名的學生成績單：企業管理（001），馬克思（002），UML （003），數據庫（004） [學生ID],[學生姓名],企業管理,馬克思,UML,數據庫,平均成績 SELECT DISTINCT top 3 SC.S# As 學生學號, Student.Sname AS 學生姓名 , T1.score AS 企業管理, T2.score AS 馬克思, T3.score AS UML, T4.score AS 數據庫, ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 總分 FROM Student,SC LEFT JOIN SC AS T1 ON SC.S# = T1.S# AND T1.C# = '001' LEFT JOIN SC AS T2 ON SC.S# = T2.S# AND T2.C# = '002' LEFT JOIN SC AS T3 ON SC.S# = T3.S# AND T3.C# = '003' LEFT JOIN SC AS T4 ON SC.S# = T4.S# AND T4.C# = '004' WHERE student.S#=SC.S# and ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) NOT IN (SELECT DISTINCT TOP 15 WITH TIES ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) FROM sc LEFT JOIN sc AS T1 ON sc.S# = T1.S# AND T1.C# = 'k1' LEFT JOIN sc AS T2 ON sc.S# = T2.S# AND T2.C# = 'k2' LEFT JOIN sc AS T3 ON sc.S# = T3.S# AND T3.C# = 'k3' LEFT JOIN sc AS T4 ON sc.S# = T4.S# AND T4.C# = 'k4' ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC);
23、統計列印各科成績,各分數段人數:課程ID,課程名稱,[100-85],[85-70],[70-60],[ 60] SELECT SC.C# as 課程ID, Cname as 課程名稱 ,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85] ,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70] ,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60] ,SUM(CASE WHEN score 60 THEN 1 ELSE 0 END) AS [60 -] FROM SC,Course where SC.C#=Course.C# GROUP BY SC.C#,Cname;
24、查詢學生平均成績及其名次 SELECT 1+(SELECT COUNT( distinct 平均成績) FROM (SELECT S#,AVG(score) AS 平均成績 FROM SC GROUP BY S# ) AS T1 WHERE 平均成績 > T2.平均成績) as 名次, S# as 學生學號,平均成績 FROM (SELECT S#,AVG(score) 平均成績 FROM SC GROUP BY S# ) AS T2 ORDER BY 平均成績 desc;
25、查詢各科成績前三名的記錄:(不考慮成績并列情況) SELECT t1.S# as 學生ID,t1.C# as 課程ID,Score as 分數 FROM SC t1 WHERE score IN (SELECT TOP 3 score FROM SC WHERE t1.C#= C# ORDER BY score DESC ) ORDER BY t1.C#; 26、查詢每門課程被選修的學生數 select c#,count(S#) from sc group by C#; 27、查詢出只選修了一門課程的全部學生的學號和姓名 select SC.S#,Student.Sname,count(C#) AS 選課數 from SC ,Student where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1; 28、查詢男生、女生人數 Select count(Ssex) as 男生人數 from Student group by Ssex having Ssex='男'; Select count(Ssex) as 女生人數 from Student group by Ssex having Ssex='女'; 29、查詢姓“張”的學生名單 SELECT Sname FROM Student WHERE Sname like '張%'; 30、查詢同名同性學生名單，并統計同名人數 select Sname,count(*) from Student group by Sname having count(*)>1;; 31、1981年出生的學生名單(注：Student表中Sage列的類型是datetime) select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age from student where CONVERT(char(11),DATEPART(year,Sage))='1981'; 32、查詢每門課程的平均成績，結果按平均成績升序排列，平均成績相同時，按課程號降序排列 Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ; 33、查詢平均成績大于85的所有學生的學號、姓名和平均成績 select Sname,SC.S# ,avg(score) from Student,SC where Student.S#=SC.S# group by SC.S#,Sname having avg(score)>85; 34、查詢課程名稱為“數據庫”，且分數低于60的學生姓名和分數 Select Sname,isnull(score,0) from Student,SC,Course where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname='數據庫'and score 60; 35、查詢所有學生的選課情況; SELECT SC.S#,SC.C#,Sname,Cname FROM SC,Student,Course where SC.S#=Student.S# and SC.C#=Course.C# ; 36、查詢任何一門課程成績在70分以上的姓名、課程名稱和分數; SELECT distinct student.S#,student.Sname,SC.C#,SC.score FROM student,Sc WHERE SC.score>=70 AND SC.S#=student.S#; 37、查詢不及格的課程，并按課程號從大到小排列 select c# from sc where scor e 60 order by C# ; 38、查詢課程編號為003且課程成績在80分以上的學生的學號和姓名; select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003'; 39、求選了課程的學生人數 select count(*) from sc; 40、查詢選修“葉平”老師所授課程的學生中，成績最高的學生姓名及其成績 select Student.Sname,score from Student,SC,Course C,Teacher where Student.S#=SC.S# and SC.C#=C.C# and C.T#=Teacher.T# and Teacher.Tname='葉平' and SC.score=(select max(score)from SC where C#=C.C# ); 41、查詢各個課程及相應的選修人數 select count(*) from sc group by C#; 42、查詢不同課程成績相同的學生的學號、課程號、學生成績 select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# >B.C# ; 43、查詢每門功成績最好的前兩名 SELECT t1.S# as 學生ID,t1.C# as 課程ID,Score as 分數 FROM SC t1 WHERE score IN (SELECT TOP 2 score FROM SC WHERE t1.C#= C# ORDER BY score DESC ) ORDER BY t1.C#; 44、統計每門課程的學生選修人數（超過10人的課程才統計）。要求輸出課程號和選修人數，查詢結果按人數降序排列，查詢結果按人數降序排列，若人數相同，按課程號升序排列 select C# as 課程號,count(*) as 人數 from sc group by C# order by count(*) desc,c# 45、檢索至少選修兩門課程的學生學號 select S# from sc group by s# having count(*) > = 2 46、查詢全部學生都選修的課程的課程號和課程名 select C#,Cname from Course where C# in (select c# from sc group by c#) 47、查詢沒學過“葉平”老師講授的任一門課程的學生姓名 select Sname from Student where S# not in (select S# from Course,Teacher,SC where Course.T#=Teacher.T# and SC.C#=course.C# and Tname='葉平'); 48、查詢兩門以上不及格課程的同學的學號及其平均成績 select S#,avg(isnull(score,0)) from SC where S# in (select S# from SC where score 60 group by S# having count(*)>2)group by S#; 49、檢索“004”課程分數小于60，按分數降序排列的同學學號 select S# from SC where C#='004'and score 60 order by score desc; 50、刪除“002”同學的“001”課程的成績 delete from Sc where S#='001'and C#='001';
