【SQL】常用数据库操作及面试问题总结 - 学生老师课程学分
2013-01-14 22:45 朱峰(Peter.zhu) 阅读(535) 评论(0) 编辑 收藏 举报
-- Student(SID,Sname,Sage,Ssex) 学生表 -- Course(CID,Cname,TID) 课程表 -- SC(SID,CID,score) 成绩表 -- Teacher(TID,Tname) 教师表 USE [TestDB] GO /****** Object: Table [dbo].[Teacher] Script Date: 01/14/2013 22:30:24 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[Teacher]( [TID] [varchar](10) NOT NULL, [Tname] [varchar](10) NULL, CONSTRAINT [PK_Teacher] PRIMARY KEY CLUSTERED ( [TID] ASC ) ON [PRIMARY] ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C01'), CONVERT(TEXT, N'王老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C02'), CONVERT(TEXT, N'朱老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C03'), CONVERT(TEXT, N'李老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C04'), CONVERT(TEXT, N'张老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C05'), CONVERT(TEXT, N'陈老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C06'), CONVERT(TEXT, N'杨老师')) INSERT [dbo].[Teacher] ([TID], [Tname]) VALUES (CONVERT(TEXT, N'C07'), CONVERT(TEXT, N'马老师')) /****** Object: Table [dbo].[Student] Script Date: 01/14/2013 22:30:24 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[Student]( [SID] [int] NOT NULL, [Sname] [varchar](10) NULL, [Ssex] [varchar](5) NULL, [Sage] [int] NULL, CONSTRAINT [PK_Student] PRIMARY KEY CLUSTERED ( [SID] ASC ) ON [PRIMARY] ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO INSERT [dbo].[Student] ([SID], [Sname], [Ssex], [Sage]) VALUES (1001, CONVERT(TEXT, N'猫猫'), CONVERT(TEXT, N'男'), 20) INSERT [dbo].[Student] ([SID], [Sname], [Ssex], [Sage]) VALUES (1002, CONVERT(TEXT, N'狗狗'), CONVERT(TEXT, N'男'), 19) INSERT [dbo].[Student] ([SID], [Sname], [Ssex], [Sage]) VALUES (1003, CONVERT(TEXT, N'猪猪'), CONVERT(TEXT, N'女'), 19) INSERT [dbo].[Student] ([SID], [Sname], [Ssex], [Sage]) VALUES (1004, CONVERT(TEXT, N'小鸟'), CONVERT(TEXT, N'男'), 21) /****** Object: Table [dbo].[SC] Script Date: 01/14/2013 22:30:24 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[SC]( [SID] [int] NULL, [CID] [varchar](10) NULL, [Score] [int] NULL ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'002'), 13) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'004'), 13) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'005'), 13) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'006'), 13) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'001'), 13) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1004, CONVERT(TEXT, N'003'), 35) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1003, CONVERT(TEXT, N'002'), 95) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1003, CONVERT(TEXT, N'001'), 55) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1001, CONVERT(TEXT, N'006'), 55) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1001, CONVERT(TEXT, N'005'), 100) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1001, CONVERT(TEXT, N'001'), 100) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1002, CONVERT(TEXT, N'001'), NULL) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1001, CONVERT(TEXT, N'002'), 90) INSERT [dbo].[SC] ([SID], [CID], [Score]) VALUES (1003, CONVERT(TEXT, N'003'), 68) /****** Object: Table [dbo].[Course] Script Date: 01/14/2013 22:30:24 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[Course]( [CID] [varchar](10) NOT NULL, [Cname] [varchar](10) NULL, [TID] [varchar](10) NULL, CONSTRAINT [PK_Course] PRIMARY KEY CLUSTERED ( [CID] ASC ) ON [PRIMARY] ) ON [PRIMARY] GO SET ANSI_PADDING OFF GO INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'001'), CONVERT(TEXT, N'自然'), CONVERT(TEXT, N'C02')) INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'002'), CONVERT(TEXT, N'社会'), CONVERT(TEXT, N'C01')) INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'003'), CONVERT(TEXT, N'心理'), CONVERT(TEXT, N'C03')) INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'004'), CONVERT(TEXT, N'地理'), CONVERT(TEXT, N'C05')) INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'005'), CONVERT(TEXT, N'数学'), CONVERT(TEXT, N'C06')) INSERT [dbo].[Course] ([CID], [Cname], [TID]) VALUES (CONVERT(TEXT, N'006'), CONVERT(TEXT, N'化学'), CONVERT(TEXT, N'C06')) --问题: --1、查询“”课程比“”课程成绩高的所有学生的学号: select distinct SID from SC as sc where (select score from sc as sc1 where CID='001' and sc1.SID=sc.SID) > (select score from sc as sc2 where CID='002' and sc2.SID=sc.SID) select SID from SC s where CID='001' and score > (select score from sc where CID='002' and s.SID = SID) select a.SID from (select SID,score from SC where CID='001') a,(select SID,score from SC where CID='002') b where a.score>b.score and a.SID=b.SID --2、查询平均成绩大于分的同学的学号和平均成绩; select SID,avg(score) from SC group by SID having avg(score)>60 --3 查询所有同学的学号、姓名、选课数、总成绩; select distinct a.SID,b.Sname, (select count(CID) as c_total from SC where SID=a.SID) as total_class, (select sum(Score) from sc where SID=a.SID) as total_score from SC as a inner join Student as b on a.SID=b.SID select Student.SID,sname,count(CID),sum(score) from SC join Student on SC.SID =Student.SID group by Student.SID,Student.sname --4 查询姓“杨”的老师的个数; select count(Tname) from Teacher where Tname like '杨%' --5、查询没学过“杨老师”老师课的同学的学号、姓名; select SID,Sname from Student where SID in (select SID from sc s,course c,teacher t where s.CID=c.CID and c.TID=t.TID and t.tname != '杨老师') --6、查询学过“”并且也学过编号“”课程的同学的学号、姓名; select SID,Sname from student where SID in (select SID from SC where CID='001' and SID in (select SID from sc where CID='002')) select s.SID,s.Sname from Student s,SC where SC.SID=s.SID and CID='001' and exists(select * from SC where CID='002' and SID=s.SID) select Student.SID,Student.Sname from Student,SC where Student.SID=SC.SID and SC.CID='001'and exists( Select * from SC as SC_2 where SC_2.SID=SC.SID and SC_2.CID='002'); --7、查询学过“杨老师”老师所教的所有课的同学的学号、姓名; select SID,Sname from student where SID in (select SID from SC s,course c,teacher t where s.CID=c.CID and c.TID=t.TID and t.tname='杨老师') select SID,sname from student where SID in(select s.SID from Course c,sc s,teacher t where t.TID = c.TID and c.CID=s.CID and t.Tname='杨老师') select SID,Sname from Student where SID in (select SID from SC ,Course ,Teacher where SC.CID=Course.CID and Teacher.TID=Course.TID and Teacher.Tname='杨老师' group by SID having count(SC.CID)=(select count(CID) from Course,Teacher where Teacher.TID=Course.TID and Tname='杨老师')); --8、查询课程编号“”的成绩比课程编号“”课程低的所有同学的学号、姓名; select SID,sname from student where SID in (select SID from sc as a where (select score from sc where CID='001' and SID=a.SID)>(select score from sc where CID='002' and SID=a.SID)) select sname,s.SID from Student s,SC where s.SID = sc.SID and CID='001' and score>(select score from sc where CID='002' and SID=s.SID) Select SID,Sname from (select Student.SID,Student.Sname,score ,(select score from SC SC_2 where SC_2.SID=Student.SID and SC_2.CID='002') score2 from Student,SC where Student.SID=SC.SID and CID='001') S_2 where score2 <score; --9、查询所有课程成绩小于分的同学的学号、姓名; select Student.SID,Sname from Student,SC where Student.SID=SC.SID group by Student.SID,Sname having avg(score)<60 select SID,Sname from Student where SID not in (select Student.SID from Student s,SC where S.SID=SC.SID and score>60); --10、查询没有学全所有课的同学的学号、姓名; select Student.SID,Student.Sname from Student,SC where Student.SID=SC.SID group by Student.SID,Student.Sname having count(CID) <(select count(CID) from Course); --11、查询至少有一门课与学号为“”的同学所学相同的同学的学号和姓名; select Student.SID,Sname from Student,SC where Student.SID=SC.SID and CID in (select CID from SC where SID='1001'); --12、查询至少学过学号为“”同学所有一门课的其他同学学号和姓名; select distinct SC.SID,Sname from Student,SC where Student.SID=SC.SID and CID in (select CID from SC where SID='1001'); --13、把“SC”表中“杨老师”老师教的课的成绩都更改为此课程的平均成绩; update SC set score = (select avg(SC_2.score) from SC SC_2 where SC_2.CID=SC.CID ) from Course,Teacher where Course.CID=SC.CID and Course.TID=Teacher.TID and Teacher.Tname='杨老师'; --14、查询和“”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 CID in (select CID from SC where SID='1002') group by SID having count(*)=(select count(*) from SC where SID='1002'); --15、删除学习“杨老师”老师课的SC表记录; Delete SC from course ,Teacher where Course.CID=SC.CID and Course.TID= Teacher.TID and Tname='杨老师'; --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“”课程的同学学号、、 号课的平均成绩; Insert SC select SID,'002',(Select avg(score) from SC where CID='002') from Student where SID not in (Select SID from SC where CID='002'); --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 SID as 学生ID ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='004') AS 数据库 ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='001') AS 企业管理 ,(SELECT score FROM SC WHERE SC.SID=t.SID AND CID='006') AS 英语 ,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩 FROM SC AS t GROUP BY SID ORDER BY avg(t.score) --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 L.CID As 课程ID,L.score AS 最高分,R.score AS 最低分 FROM SC L ,SC AS R WHERE L.CID = R.CID and L.score = (SELECT MAX(IL.score) FROM SC AS IL,Student AS IM WHERE L.CID = IL.CID and IM.SID=IL.SID GROUP BY IL.CID) AND R.Score = (SELECT MIN(IR.score) FROM SC AS IR WHERE R.CID = IR.CID GROUP BY IR.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 t.CID AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0) AS 平均成绩 ,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数 FROM SC T,Course where t.CID=course.CID GROUP BY t.CID ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) 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(),马克思(),OO&UML (),数据库() SELECT SUM(CASE WHEN CID ='001' THEN score ELSE 0 END)/SUM(CASE CID WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分 ,100 * SUM(CASE WHEN CID = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数 ,SUM(CASE WHEN CID = '002' THEN score ELSE 0 END)/SUM(CASE CID WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分 ,100 * SUM(CASE WHEN CID = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数 ,SUM(CASE WHEN CID = '003' THEN score ELSE 0 END)/SUM(CASE CID WHEN '003' THEN 1 ELSE 0 END) AS UML平均分 ,100 * SUM(CASE WHEN CID = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '003' THEN 1 ELSE 0 END) AS UML及格百分数 ,SUM(CASE WHEN CID = '004' THEN score ELSE 0 END)/SUM(CASE CID WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分 ,100 * SUM(CASE WHEN CID = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN CID = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数 FROM SC --21、查询不同老师所教不同课程平均分从高到低显示 SELECT max(Z.TID) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.CID AS 课程ID,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩 FROM SC AS T,Course AS C ,Teacher AS Z where T.CID=C.CID and C.TID=Z.TID GROUP BY C.CID ORDER BY AVG(Score) DESC --22、查询如下课程成绩第3 名到第6 名的学生成绩单:企业管理(),马克思(),UML (),数据库() --[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩 SELECT DISTINCT top 3 SC.SID As 学生学号, Student.Sname AS 学生姓名, T1.score AS 企业管理, T2.score AS 马克思, T3.score AS UML, T4.score AS 数据库, ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 总分 FROM Student,SC LEFT JOIN SC AS T1 ON SC.SID = T1.SID AND T1.CID = '001' LEFT JOIN SC AS T2 ON SC.SID = T2.SID AND T2.CID = '002' LEFT JOIN SC AS T3 ON SC.SID = T3.SID AND T3.CID = '003' LEFT JOIN SC AS T4 ON SC.SID = T4.SID AND T4.CID = '004' WHERE student.SID=SC.SID 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.SID = T1.SID AND T1.CID = 'k1' LEFT JOIN sc AS T2 ON sc.SID = T2.SID AND T2.CID = 'k2' LEFT JOIN sc AS T3 ON sc.SID = T3.SID AND T3.CID = 'k3' LEFT JOIN sc AS T4 ON sc.SID = T4.SID AND T4.CID = 'k4' ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC); --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],[ <60] SELECT SC.CID as 课程ID, Cname as 课程名称 ,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.CID=Course.CID GROUP BY SC.CID,Cname; --24、查询学生平均成绩及其名次 SELECT 1+(SELECT COUNT( distinct 平均成绩) FROM (SELECT SID,AVG(score) AS 平均成绩 FROM SC GROUP BY SID ) AS T1 WHERE 平均成绩> T2.平均成绩) as 名次, SID as 学生学号,平均成绩 FROM (SELECT SID,AVG(score) 平均成绩 FROM SC GROUP BY SID ) AS T2 ORDER BY 平均成绩 desc; --25、查询各科成绩前三名的记录:(不考虑成绩并列情况) SELECT t1.SID as 学生ID,t1.CID as 课程ID,Score as 分数 FROM SC t1 WHERE score IN (SELECT TOP 3 score FROM SC WHERE t1.CID= CID ORDER BY score DESC ) ORDER BY t1.CID; --26、查询每门课程被选修的学生数 select CID,count(SID) from sc group by CID; --27、查询出只选修了一门课程的全部学生的学号和姓名 select SC.SID,Student.Sname,count(CID) AS 选课数 from SC ,Student where SC.SID=Student.SID group by SC.SID ,Student.Sname having count(CID)=1; --28、查询男生、女生人数 Select count(Ssex) as 男生人数 from Student group by Ssex having Ssex='男' Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='女' --29、查询姓“张”的学生名单 SELECT Sname FROM Student WHERE Sname like '张%'; --30、查询同名同性学生名单,并统计同名人数 select Sname,count(*) from Student group by Sname having count(*)>1;; --31、年出生的学生名单(注:Student表中Sage列的类型是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,Avg(score) from SC group by CID order by Avg(score),CID DESC ; --33、查询平均成绩大于的所有学生的学号、姓名和平均成绩 select Sname,SC.SID ,avg(score) from Student,SC where Student.SID=SC.SID group by SC.SID,Sname having avg(score)>85; --34、查询课程名称为“数据库”,且分数低于的学生姓名和分数 Select Sname,isnull(score,0) from Student,SC,Course where SC.SID=Student.SID and SC.CID=Course.CID and Course.Cname='数据库'and score <60; --35、查询所有学生的选课情况; SELECT SC.SID,SC.CID,Sname,Cname FROM SC,Student,Course where SC.SID=Student.SID and SC.CID=Course.CID ; --36、查询任何一门课程成绩在分以上的姓名、课程名称和分数; SELECT distinct student.SID,student.Sname,SC.CID,SC.score FROM student,Sc WHERE SC.score>=70 AND SC.SID=student.SID; --37、查询不及格的课程,并按课程号从大到小排列 select CID from sc where score < 60 order by CID ; --38、查询课程编号为且课程成绩在分以上的学生的学号和姓名; select SC.SID,Student.Sname from SC,Student where SC.SID=Student.SID and Score>80 and CID='003'; --39、求选了课程的学生人数 select count(*) from sc; --40、查询选修“杨老师”老师所授课程的学生中,成绩最高的学生姓名及其成绩 select Student.Sname,score from Student,SC,Course C,Teacher where Student.SID=SC.SID and SC.CID=C.CID and C.TID=Teacher.TID and Teacher.Tname='杨老师' and SC.score=(select max(score)from SC where CID=C.CID ); --41、查询各个课程及相应的选修人数 select count(*) from sc group 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 distinct A.SID,B.score from SC A ,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 t1.SID as 学生ID,t1.CID as 课程ID,Score as 分数 FROM SC t1 WHERE score IN (SELECT TOP 2 score FROM SC WHERE t1.CID= CID ORDER BY score DESC ) ORDER BY t1.CID; --44、统计每门课程的学生选修人数(超过人的课程才统计)。要求输出课程号和选修人数, -- 查询结果按人数降序排列,查询结果按人数降序排列,若人数相同,按课程号升序排列 select CID as 课程号,count(*) as 人数 from sc group by CID order by count(*) desc,CID --45、检索至少选修两门课程的学生学号 select SID from sc group by SID 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 CID,Cname from Course where CID in (select CID from sc group by CID) --47、查询没学过“杨老师”老师讲授的任一门课程的学生姓名 select Sname from Student where SID not in (select SID from Course,Teacher,SC where Course.TID=Teacher.TID and SC.CID=course.CID and Tname='杨老师'); --48、查询两门以上不及格课程的同学的学号及其平均成绩 select SID,avg(isnull(score,0)) from SC where SID in (select SID from SC where score <60 group by SID having count(*)>2)group by SID; --49、检索“”课程分数小于,按分数降序排列的同学学号 select SID from SC where CID='004'and score <60 order by score desc; --50、删除“”同学的“”课程的成绩 delete from Sc where SID='001'and CID='001';