常見的sql面試題.docx

學生表 :Student (S1,Sname,Sage,Ssex) S1：學號； Sname：學生姓名； Sage：學生年齡； Ssex：學生性別課程表 : Course(C1,Cname,T1) C1,課程編號；Cname：課程名字；T1：教師編號成績表: SC(S1,C1,score) S1：學號；C1,課程編號；score：成績教師表 :Teacher(T,#Tname) T1：教師編號； Tname：教師名字問題：1、查詢“001”課程比“002”課程成績高的所有學生的學號； select a.S1 from (select S1,score from SC where C1=001) a,(select S1,score from SC where C1=002) b where a.scoreb.score and a.S1=b.S1;2、查詢平均成績大于60分的同學的學號和平均成績； select S1,avg(score) from sc group by S1 having avg(score) 60;3、查詢所有同學的學號、姓名、選課數(shù)、總成績； select Student.S1,Student.Sname,count(SC.C1),sum(score) from Student left Outer join SC on Student.S1=SC.S1 group by Student.S1,Sname4、查詢姓“李”的老師的個數(shù)； 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.S1,Student.Sname from Student where S1 not in (select distinct( SC.S1) from SC,Course,Teacher where SC.C1=Course.C1 and Teacher.T1=Course.T1 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.S1,Student.Sname from Student,SC where Student.S1=SC.S1 and SC.C1=001and exists( Select * from SC as SC_2 where SC_2.S1=SC.S1 and SC_2.C1=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 S1,Sname from Student where S1 in (select S1 from SC ,Course ,Teacher where SC.C1=Course.C1 and Teacher.T1=Course.T1 and Teacher.Tname=葉平 group by S1 having count(SC.C1)=(select count(C1) from Course,Teacher where Teacher.T1=Course.T1 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 S1,Sname from (select Student.S1,Student.Sname,score ,(select score from SC SC_2 where SC_2.S1=Student.S1 and SC_2.C1=002) score2 from Student,SC where Student.S1=SC.S1 and C1=001) S_2 where score2 60);10、查詢沒有學全所有課的同學的學號、姓名； select Student.S1,Student.Sname from Student,SC where Student.S1=SC.S1 group by Student.S1,Student.Sname having count(C1) =60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分數(shù) FROM SC T,Course where t.C1=course.C1 GROUP BY t.C1 ORDER BY 100 * SUM(CASE WHEN isnull(score,0)=60 THEN 1 ELSE 0 END)/COUNT(*) DESC20、查詢?nèi)缦抡n程平均成績和及格率的百分數(shù)(用1行顯示): 企業(yè)管理（001），馬克思（002），OO&UML （003），數(shù)據(jù)庫（004） SELECT SUM(CASE WHEN C1 =001 THEN score ELSE 0 END)/SUM(CASE C1 WHEN 001 THEN 1 ELSE 0 END) AS 企業(yè)管理平均分 ,100 * SUM(CASE WHEN C1 = 001 AND score = 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C1 = 001 THEN 1 ELSE 0 END) AS 企業(yè)管理及格百分數(shù) ,SUM(CASE WHEN C1 = 002 THEN score ELSE 0 END)/SUM(CASE C1 WHEN 002 THEN 1 ELSE 0 END) AS 馬克思平均分 ,100 * SUM(CASE WHEN C1 = 002 AND score = 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C1 = 002 THEN 1 ELSE 0 END) AS 馬克思及格百分數(shù) ,SUM(CASE WHEN C1 = 003 THEN score ELSE 0 END)/SUM(CASE C1 WHEN 003 THEN 1 ELSE 0 END) AS UML平均分 ,100 * SUM(CASE WHEN C1 = 003 AND score = 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C1 = 003 THEN 1 ELSE 0 END) AS UML及格百分數(shù) ,SUM(CASE WHEN C1 = 004 THEN score ELSE 0 END)/SUM(CASE C1 WHEN 004 THEN 1 ELSE 0 END) AS 數(shù)據(jù)庫平均分 ,100 * SUM(CASE WHEN C1 = 004 AND score = 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C1 = 004 THEN 1 ELSE 0 END) AS 數(shù)據(jù)庫及格百分數(shù) FROM SC21、查詢不同老師所教不同課程平均分從高到低顯示 SELECT max(Z.T1) AS 教師ID,MAX(Z.Tname) AS 教師姓名,C.C1 AS 課程,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.C1=C.C1 and C.T1=Z.T1 GROUP BY C.C1 ORDER BY AVG(Score) DESC22、查詢?nèi)缦抡n程成績第 3 名到第 6 名的學生成績單：企業(yè)管理（001），馬克思（002），UML （003），數(shù)據(jù)庫（004） 學生ID,學生姓名,企業(yè)管理,馬克思,UML,數(shù)據(jù)庫,平均成績 SELECT DISTINCT top 3 SC.S1 As 學生學號, Student.Sname AS 學生姓名 , T1.score AS 企業(yè)管理, T2.score AS 馬克思, T3.score AS UML, T4.score AS 數(shù)據(jù)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.S1 = T1.S1 AND T1.C1 = 001 LEFT JOIN SC AS T2 ON SC.S1 = T2.S1 AND T2.C1 = 002 LEFT JOIN SC AS T3 ON SC.S1 = T3.S1 AND T3.C1 = 003 LEFT JOIN SC AS T4 ON SC.S1 = T4.S1 AND T4.C1 = 004 WHERE student.S1=SC.S1 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.S1 = T1.S1 AND T1.C1 = k1 LEFT JOIN sc AS T2 ON sc.S1 = T2.S1 AND T2.C1 = k2 LEFT JOIN sc AS T3 ON sc.S1 = T3.S1 AND T3.C1 = k3 LEFT JOIN sc AS T4 ON sc.S1 = T4.S1 AND T4.C1 = k4 ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC);23、統(tǒng)計列印各科成績,各分數(shù)段人數(shù):課程ID,課程名稱,100-85,85-70,70-60, 60 SELECT SC.C1 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 T2.平均成績) as 名次, S1 as 學生學號,平均成績 FROM (SELECT S1,AVG(score) 平均成績 FROM SC GROUP BY S1 ) 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.S1 as 學生ID,t1.C1 as 課程ID,Score as 分數(shù) FROM SC t1 WHERE score IN (SELECT TOP 3 score FROM SC WHERE t1.C1= C1 ORDER BY score DESC ) ORDER BY t1.C1;26、查詢每門課程被選修的學生數(shù) select C1,count(S1) from sc group by C1;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.S1,Student.Sname,count(C1) AS 選課數(shù) from SC ,Student where SC.S1=Student.S1 group by SC.S1 ,Student.Sname having count(C1)=1;28、查詢男生、女生人數(shù) Select count(Ssex) as 男生人數(shù) from Student group by Ssex having Ssex=男; Select count(Ssex) as 女生人數(shù) 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(tǒng)計同名人數(shù) 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(jié)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 C1,Avg(score) from SC group by C1 order by Avg(score),C1 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.S1 ,avg(score) from Student,SC where Student.S1=SC.S1 group by SC.S1,Sname having avg(score)85;34、查詢課程名稱為“數(shù)據(jù)庫”，且分數(shù)低于60的學生姓名和分數(shù) Select Sname,isnull(score,0) from Student,SC,Course where SC.S1=Student.S1 and SC.C1=Course.C1 and Course.Cname=數(shù)據(jù)庫and score =70 AND SC.S1=student.S1;37、查詢不及格的課程，并按課程號從大到小排列 select C1 from sc where scor e 80 and C1=003;39、求選了課程的學生人數(shù) 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.S1=SC.S1 and SC.C1=C.C1 and C.T1=Teacher.T1 and Teacher.Tname=葉平 and SC.score=(select max(score)from SC where C1=C.C1 );41、查詢各個課程及相應(yīng)的選修人數(shù) select count(*) from sc group by C1;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.S1,B.score from SC A ,SC B where A.Score=B.Score and A.C1 B.C1 ;43、查詢每門功成績最好的前兩名 SELECT t1.S1 as 學生ID,t1.C1 as 課程ID,Score as 分數(shù) FROM SC t1 WHERE score IN (SELECT TOP 2 score FROM SC WHERE t1.C1= C1 ORDER BY score DESC ) ORDER BY t1.C1;44、統(tǒng)計每門課程的學生選修人數(shù)（超過10人的課程才統(tǒng)計）