sql

摘要： --1.学生表 Student(S,Sname,Sage,Ssex) --S 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别 --2.课程表  Course(C,Cname,T) --C --课程编号,Cname 课程名称,T 教师编号 --3.

--1.学生表
Student(S,Sname,Sage,Ssex) --S 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别
--2.课程表 
Course(C,Cname,T) --C --课程编号,Cname 课程名称,T 教师编号
--3.教师表 
Teacher(T,Tname) --T 教师编号,Tname 教师姓名
--4.成绩表 
SC(S,C,score) --S 学生编号,C 课程编号,score 分数
*/
--创建测试数据

create table Student(S varchar(10),Sname varchar(10),Sage datetime,Ssex nvarchar(10))insert into Student values('01' , '赵雷' , '1990-01-01' , '男')insert into Student values('02' , '钱电' , '1990-12-21' , '男')insert into Student values('03' , '孙风' , '1990-05-20' , '男')insert into Student values('04' , '李云' , '1990-08-06' , '男')insert into Student values('05' , '周梅' , '1991-12-01' , '女')insert into Student values('06' , '吴兰' , '1992-03-01' , '女')insert into Student values('07' , '郑竹' , '1989-07-01' , '女')insert into Student values('08' , '王菊' , '1990-01-20' , '女')create table Course(C varchar(10),Cname,varchar(10),T varchar(10))insert into Course values('01' , '语文' , '02')insert into Course values('02' , '数学' , '01')insert into Course values('03' , '英语' , '03')create table Teacher(T varchar(10),Tname,varchar(10))insert into Teacher values('01' , '张三')insert into Teacher values('02' , '李四')insert into Teacher values('03' , '王五')create table SC(S varchar(10),C varchar(10),score decimal(18,1))insert into SC values('01' , '01' , 80)insert into SC values('01' , '02' , 90)insert into SC values('01' , '03' , 99)insert into SC values('02' , '01' , 70)insert into SC values('02' , '02' , 60)insert into SC values('02' , '03' , 80)insert into SC values('03' , '01' , 80)insert into SC values('03' , '02' , 80)insert into SC values('03' , '03' , 80)insert into SC values('04' , '01' , 50)insert into SC values('04' , '02' , 30)insert into SC values('04' , '03' , 20)insert into SC values('05' , '01' , 76)insert into SC values('05' , '02' , 87)insert into SC values('06' , '01' , 31)insert into SC values('06' , '03' , 34)insert into SC values('07' , '02' , 89)insert into SC values('07' , '03' , 98)

--1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数

SELECT a.* ,c.* from (select     a.*        from(SELECT * from sc WHERE sc.C in('01'))aleft JOIN(SELECT * from sc where sc.C in('02'))bON a.s =b.s where a.score>b.score ) a ,student cwhere a.s =c.s;

SELECT a.*FROM/*sc中c=01*/(SELECT * FROM SC WHERE SC.`C`IN('01'))aLEFT JOIN/*sc中c=02*/(SELECT * FROM SC WHERE SC.`C`IN('02'))bON /*A,B中s相同*/a.S=b.S WHERE /*并且a的score大*/a.score>b.score

--2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数

SELECT a.* ,c.*FROM(SELECT a.*FROM(SELECT * FROM sc WHERE sc.C in('01'))aLEFT JOIN(SELECT * FROM sc WHERE sc.C in('02'))bON a.s =b.s WHERE a.score<b.score) a,student cWHERE a.s =c.s

--3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩

SELECTb.s,c.Sname,b.avgscoreFROM   /*通过group                 by分组平均groupby分组的字段*/(SELECT     a.s s    , avg(a.score) avgscoreFROM sc aGROUP BY a.s) b    ,student cWHEREb.avgscore>60 AND c.s =b.s

--4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩

SELECTb.s,c.Sname,b.avgscoreFROM(SELECT     a.s s    , avg(a.score) avgscoreFROM sc aGROUP BY a.s) b    ,student cWHEREb.avgscore<60 AND c.s =b.s

--5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩

SELECT    b.s    ,c.Sname    ,b.num    ,b.sumscore    FROM(SELECT    a.s s    ,COUNT(a.c) num     ,SUM(a.score) sumscoreFROM     sc aGROUP BY a.s) b    ,student cWHERE b.s =c.s

--6、查询"李"姓老师的数量 

SELECTCOUNT(a.Tname)FROM(SELECT    Tname TnameFROM    teacher    WHERE    Tname LIKE '李%') a

--7、查询学过"张三"老师授课的同学的信息 

SELECTd.*FROMstudent d,sc eWHEREe.S =d.SANDe.C=(SELECT    b.CFROM    teacher a    ,course bWHERE    a.T =b.T AND a.Tname='张三') 

--8、查询没学过"张三"老师授课的同学的信息 

SELECTa.*FROMstudent aWHEREa.S NOT in (SELECT  b.SFROMsc a,student bWHEREa.S=b.S ANDa.C =(SELECT    b.c FROM    teacher a    ,course bWHERE    a.T =b.T AND a.Tname ='张三'))

--9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息

SELECT*FROM sc a,sc b,student cWHEREa.S =b.S AND a.C='01' and b.C='02'    AND c.S =a.S

--10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息

SELECT*FROMstudent aWHEREa.S in(SELECTDISTINCT(sc.s)FROMscWHEREsc.SNOTin(SELECT SFROM scWHERE sc.C in('02')GROUP BYsc.S))

--11、查询没有学全所有课程的同学的信息 

SELECTb.*FROMstudent bWHEREb.S in(SELECTa.sFROM(SELECT    a.S s    ,COUNT(a.C) NUMFROMsc aGROUP BYa.s) aWHEREa.NUM<3)

--12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息 

SELECTe.*FROMstudent eWHEREe.S in (SELECTDISTINCT(c.s)FROMstudent c,sc dWHEREc.s=d.sAND d.C in (SELECT b.cFROM student a,sc  bWHEREa.s =b.s AND a.s ='01'))

--13、查询和"01"号的同学学习的课程完全相同的其他同学的信息 

SELECT    a.cFROM    sc a    WHERE    a.S ='01'                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       ---SELECT*FROM(SELECTa.*,COUNT(b.c) numFROMstudent a,sc bWHEREa.s=b.S GROUP BYb.S) aWHEREa.num=3 AND a.s <> '01'

--14、查询没学过"张三"老师讲授的任一门课程的学生姓名 

SELECT*FROMstudent aWHEREa.S NOT in (SELECTb.SFROM(SELECTb.c ,b.CnameFROMteacher a,course bWHEREa.T=b.TANDa.Tname='张三') a,sc bWHEREa.c=b.C)

--15、查询两门及其以上不及格课程的同学的学号，姓名及其平均成绩 

SELECTb.S,b.Sname,a.avgscoreFROM(SELECTAVG(score) avgscore,s SFROMscWHEREsc.score<60GROUP BYsHAVING COUNT(s)>=2) a,student bWHEREa.S=b.S

--16、检索"01"课程分数小于60，按分数降序排列的学生信息

SELECTb.*FROM(SELECTa.s sFROMsc aWHEREa.C ='01'ANDa.score<60ORDER BY a.score DESC) a,student bWHEREa.s=b.S

--17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩

SELECT*FROM(SELECTb.S,b.C,b.score,c.avgscoreFROMsc bLEFT JOIN(SELECTa.S,AVG(a.score) avgscoreFROMsc aGROUP BY a.S) cON c.S =b.S) a,student bWHEREa.S =b.SORDER BY avgscore DESC

--18、查询各科成绩最高分、最低分和平均分：以如下形式显示：课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率
--及格为>=60，中等为：70-80，优良为：80-90，优秀为：>=90

SELECTa.C,b.Cname,MAX(a.score),MIN(a.score),AVG(a.score),(SELECT COUNT(1) FROM sc WHERE sc.C=b.C and score>60)/(SELECT COUNT(1)FROM sc WHERE sc.C=b.c ) jigelvFROM sc a ,course b WHERE a.C =b.CGROUP BYa.C

SELECTa.C,a.Cname,MAX(b.score),MIN(b.score),CAST(AVG(b.score) AS DECIMAL(18,2)) pingqunfen,CAST((SELECT COUNT(1) FROM sc WHERE sc.C=a.C AND sc.score>60)/(SELECT COUNT(1) FROM sc WHERE sc.C =a.C) AS DECIMAL(18,2)) jigelv,CAST((SELECT COUNT(1) FROM sc WHERE sc.C =a.c AND sc.score>=70 AND sc.score<80)/(SELECT COUNT(1) FROM sc WHERE sc.c =a.c) AS DECIMAL (18,2)) youlianlvFROMcourse a,sc bWHEREa.C=b.CGROUP BY a.C,a.CnameORDER BY a.C DESC

--19、按各科成绩进行排序，并显示排名

SELECT c.s,c.sname,b.cname,a.score,(SELECT COUNT(1) FROM sc WHERE sc.C=a.c AND sc.score > a.score)+1 mcFROM sc a ,course b,student c WHERE a.c='01'AND a.c=b.c AND a.s=c.sORDER BY mc

SELECT c.s,c.sname,b.cname,a.score,(SELECT COUNT(1) FROM sc WHERE sc.C=a.c AND sc.score > a.score)+1 mcFROM sc a ,course b,student c WHERE a.c='02'AND a.c=b.c AND a.s=c.sORDER BY mc

SELECT c.s,c.sname,b.cname,a.score,(SELECT COUNT(1) FROM sc WHERE sc.C=a.c AND sc.score > a.score)+1 mcFROM sc a ,course b,student c WHERE a.c='03'AND a.c=b.c AND a.s=c.sORDER BY mc

--20、查询学生的总成绩并进行排名

SELECT b.s,b.sumscore,@rownum:=@rownum +1 AS rownumFROM(SELECTa.s s,SUM(a.score) sumscoreFROMsc aGROUP BYa.SORDER BY sumscore DESC) as b,(SELECT @rownum:=0)r

--21、查询不同老师所教不同课程平均分从高到低显示 

SELECTc.Tname,b.Cname,AVG(a.score) FROMsc a,course b,teacher cWHEREa.C =b.CAND b.T =c.TGROUP BY a.CORDER BY AVG(a.score) DESC

--22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩

SELECTa.*,b.*FROM(SELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='01'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='01' HAVING mc BETWEEN 2 AND 3UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='02'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='02' HAVING mc BETWEEN 2 AND 3UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='03'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='03' HAVING mc BETWEEN 2 AND 3) a,student bWHEREa.s =b.s

--23、统计各科成绩各分数段人数：课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比 

SELECTa.*FROM(SELECTc.Cname,(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c AND c.c=a.C AND  a.C='01') '85以上',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c AND c.c=a.C AND a.score>70 AND a.C='01') '[70_85]',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='01') '[60_70]',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c  AND c.c=a.C AND a.C='01') '60一下',(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c  AND c.c=a.C AND a.C='01')/(SELECT COUNT(*)FROM sc WHERE c='01'AND C=b.c AND c.c=c) '85以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c  AND c.c=a.C AND a.score>70 AND a.C='01')/(SELECT COUNT(*)FROM sc WHERE c='01'AND C=b.c AND c.c=c) '[70_85]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='01')/(SELECT COUNT(*)FROM sc WHERE c='01'AND C=b.c AND c.c=c)'[60_70]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c AND c.c=a.C  AND a.C='01')/(SELECT COUNT(*)FROM sc WHERE c='01'AND C=b.c AND c.c=c)'60以上比率'FROM sc b ,course c WHERE b.c=c.c AND c.c='01'UNION ALLSELECTc.Cname,(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c AND c.c=a.C AND  a.C='02') '85以上',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c AND c.c=a.C AND a.score>70 AND a.C='02') '[70_85]',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='02') '[60_70]',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c  AND c.c=a.C AND a.C='02') '60一下',(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c  AND c.c=a.C AND a.C='02')/(SELECT COUNT(*)FROM sc WHERE c='02'AND C=b.c AND c.c=c) '85以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c  AND c.c=a.C AND a.score>70 AND a.C='02')/(SELECT COUNT(*)FROM sc WHERE c='02'AND C=b.c AND c.c=c)'[70_85]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='02')/(SELECT COUNT(*)FROM sc WHERE c='02'AND C=b.c AND c.c=c)'[60_70]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c AND c.c=a.C  AND a.C='02')/(SELECT COUNT(*)FROM sc WHERE c='02'AND C=b.c AND c.c=c)'60以上比率'FROM sc b ,course c WHERE b.c=c.c AND c.c='02'UNION ALLSELECTc.Cname,(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c AND c.c=a.C AND  a.C='03') '85以上',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c AND c.c=a.C AND a.score>70 AND a.C='03') '[70_85]',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='03') '[60_70]',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c  AND c.c=a.C AND a.C='03') '60一下',(SELECT COUNT(*)FROM sc a WHERE a.score>85 AND a.C=b.c  AND c.c=a.C AND a.C='03')/(SELECT COUNT(*)FROM sc WHERE c='03'AND C=b.c AND c.c=c) '85以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<85 AND a.C=b.c  AND c.c=a.C AND a.score>70 AND a.C='03')/(SELECT COUNT(*)FROM sc WHERE c='03'AND C=b.c AND c.c=c)'[70_85]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score>70 AND a.C=b.c  AND c.c=a.C AND a.score>60 AND a.C='03')/(SELECT COUNT(*)FROM sc WHERE c='03'AND C=b.c AND c.c=c)'[60_70]以上比率',(SELECT COUNT(*)FROM sc a WHERE a.score<60 AND a.C=b.c AND c.c=a.C  AND a.C='01')/(SELECT COUNT(*)FROM sc WHERE c='03'AND C=b.c AND c.c=c)'60以上比率'FROM sc b ,course c WHERE b.c=c.c AND c.c='03') a

--24、查询学生平均成绩及其名次 

SELECTa.s,a.avgscore,@rownum:=@rownum +1 AS rownumFROM (SELECTs,AVG(score) avgscoreFROMsc GROUP BY sORDER BY avgscore DESC) a,(SELECT @rownum:=0)r

--25、查询各科成绩前三名的记录

SELECTa.*,b.*FROM(SELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='01'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='01' HAVING mc BETWEEN 1 AND 3UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='02'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='02' HAVING mc BETWEEN 1 AND 3UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='03'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='03' HAVING mc BETWEEN 1 AND 3) a,student bWHEREa.s =b.s

--26、查询每门课程被选修的学生数 

SELECTa.Cname,COUNT(b.c)FROM sc b,course a WHERE a.c =b.cGROUP BY b.c

--27、查询出只有两门课程的全部学生的学号和姓名  

SELECTb.S,b.Sname,a.countcFROM(SELECTs ,COUNT(c) countcFROM scGROUP BY sHAVING countc =2) a,student bWHEREa.s=b.s

--28、查询男生、女生人数 

select s.Ssex,COUNT(*)from student s where s.Ssex='男'UNIONselect s.Ssex,COUNT(*)from student s where s.Ssex='女'

--29、查询名字中含有"风"字的学生信息

SELECT*,count(*)FROM student WHERESname rLIKE '风'

--30、查询同名同性学生名单，并统计同名人数 

SELECTs.Sname,s.Ssex,COUNT(*) countnumfromstudent sGROUP BYs.Sname,s.SsexHAVINGcountnum>=2

--31、查询1990年出生的学生名单(注：Student表中Sage列的类型是datetime) 

SELECT*FROMstudentWHERESage LIKE '1990%'

--32、查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号

SELECTa.Cname,AVG(sc.score) avgscoreFROM sc ,course aWHERE sc.C =a.CGROUP BY sc.CORDER BY avgscore DESC

--33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩 

SELECT*FROM(SELECTa.Sname,a.S,AVG(sc.score) avgscoreFROM sc ,student aWHERE sc.s =a.s GROUP BY sc.sORDER BY avgscore DESC) aWHEREa.avgscore>85

--34、查询课程名称为"数学"，且分数低于60的学生姓名和分数 

SELECT*FROMsc a,course bWHERE a.c =b.c AND b.Cname='数学' AND a.score>60

--35、查询所有学生的课程及分数情况；

SELECT*FROMstudent a,course b,sc cWHEREa.S=c.S AND b.C =c.C

--36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数； 

SELECTb.Sname,c.Cname,a.scoreFROMsc  a, student b,course cWHEREa.score>70 AND a.C =c.C AND a.S =b.S

--37、查询不及格的课程

SELECTb.Sname,c.Cname,a.scoreFROMsc  a, student b,course cWHEREa.score<60 AND a.C =c.C AND a.S =b.S

--38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名； 

SELECTc.S,c.Sname,a.Cname,b.scoreFROMcourse a ,sc b ,student cWHERE a.C =b.C AND b.score>=80 AND c.S =b.S AND a.C='01'

--39、求每门课程的学生人数 

SELECTb.Cname,COUNT(a.c)FROMsc a ,course bWHEREb.c=a.CGROUP BYa.C

--40、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩

SELECTb.*,MAX(c.score)FROMteacher a,student b ,sc c ,course dWHEREa.T =d.T AND d.C =c.C AND c.S =b.S AND  a.Tname ='张三'

--41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩 

SELECT c.* FROM sc c GROUP BY c.`C`,c.`score` HAVING COUNT(*)>1;

--42、查询每门功成绩最好的前两名 

SELECTa.*,b.*FROM(SELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='01'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='01' HAVING mc BETWEEN 1 AND 2UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='02'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='02' HAVING mc BETWEEN 1 AND 2UNION ALLSELECT b.s ,b.C ,b.score,(SELECT COUNT(*) FROM sc a WHERE a.c='03'AND a.score>b.score)+1 mcFROM sc b  WHERE b.c='03' HAVING mc BETWEEN 1 AND 2) a,student bWHEREa.s =b.s

--43、统计每门课程的学生选修人数（超过5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，若人数相同，按课程号升序排列  

SELECTb.C,b.Cname ,COUNT(a.C) countcFROMsc a,course bWHEREa.c=b.C GROUP BYa.CHAVING countc>5ORDER BY countc DESC

--44、检索至少选修两门课程的学生学号 

SELECTsc.S,COUNT(sc.C) countcFROMscGROUP BY sc.SHAVING countc >=2

--45、查询选修了全部课程的学生信息 

SELECTa.*,COUNT(sc.C) countcFROMsc ,student  aWHERE sc.S =a.SGROUP BY sc.SHAVING countc =3

--46、查询各学生的年龄

SELECT    s.s,    s.sname,    EXTRACT(YEAR FROM NOW())-EXTRACT(YEAR FROM s.sage) 年龄FROM    student s

--47、查询本周过生日的学生

SELECTs.S,s.Sname,s.SageFROM student sWHERE YEARWEEK(DATE_FORMAT(s.Sage,'%Y-%m-%d')) =YEARWEEK(NOW())

--48、查询下周过生日的学生

SELECTs.S,s.Sname,s.SageFROM student sWHERE YEARWEEK(DATE_FORMAT(s.Sage,'%Y-%m-%d')) =YEARWEEK(NOW())+1

--49、查询本月过生日的学生

SELECTs.S,s.Sname,s.SageFROM student sWHERE MONTH(DATE_FORMAT(s.Sage,'%Y-%m-%d')) =MONTH(NOW())

--50、查询下月过生日的学生

SELECTs.S,s.Sname,s.SageFROM student sWHERE MONTH(DATE_FORMAT(s.Sage,'%Y-%m-%d')) =MONTH(NOW())+1