SQL 增删改查45道题

create database School
use School
go
create table Student  --1.学生表
(
    Sno varchar(20) not null primary key,--学号（主码）
    Sname varchar(20) not null,--学生姓名
    Ssex varchar(20) not null,--学生性别
    Sbirthday datetime,--学生出生年月
    Class varchar(20),--学生所在班级
)
go
create table Teacher   --4.教师表
(
    Tno varchar(20) not null primary key,--教工编号（主）
    Tname varchar(20) not null,--教工姓名
    Tsex varchar(20) not null,--教工性别
    Tbirthday datetime,--教工出生年月
    Prof varchar(20),--职称
    Depart varchar(20) not null,--教工所在部门
)
go
create table Course    --2.课程表
(
    Cno varchar(20) not null primary key,--课程号（主）
    Cname varchar(20) not null,--课程名称
    Tno varchar(20) not null references Teacher(Tno),--教工编号（外）
)
go
create table Score    --3.成绩表
(
    Sno varchar(20) not null references Student(Sno),--学号（外）
    Cno varchar(20) not null references Course(Cno),--课程号（外）
    Degree decimal(4,1),--成绩
)
alter table Score add constraint Pk_Score primary key (Sno,Cno) --添加两个主键
 
--学生信息
insert into Student values('','曾华','男','1977-09-01','')
insert into Student(Sno,Sname,Ssex,Sbirthday,Class)values('','匡明','男','1975-10-02','')
insert into Student values('','王丽','女','1976-01-23','')
insert into Student values('','李军','男','1976-02-20','')
insert into Student values('','王芳','女','1975-02-10','')
insert into Student values('','陆君','男','1974-06-03','')
--职工信息
insert into Teacher values('','李诚','男','1958-12-02','副教授','计算机系')
insert into Teacher values('','张旭','男','1969-03-12','讲师','电子工程系')
insert into Teacher values('','王萍','女','1972-05-05','助教','计算机系')
insert into Teacher values('','刘冰','女','1977-08-14','助教','电子工程系')
--课程
insert into Course values('3-105','计算机导论','')
insert into Course values('3-245','操作系统','')
insert into Course values('6-166','数字电路','')
insert into Course values('9-888','高等数学','')
--成绩
insert into Score values('','3-245','')
insert into Score values('','3-245','')
insert into Score values('','3-245','')
insert into Score values('','3-105','')
insert into Score values('','3-105','')
insert into Score values('','3-105','')
insert into Score values('','3-105','')
insert into Score values('','3-105','')
insert into Score values('','3-105','')
insert into Score values('','6-166','')
insert into Score values('','6-166','')
insert into Score values('','6-166','')
--1、 查询Student表中的所有记录的Sname、Ssex和Class列。
select Sname,Ssex,Class from Student
--2、 查询教师所有的单位即不重复的Depart列。
--去重 distinct
select distinct Depart from Teacher
--3、 查询Student表的所有记录。
select * from Student
--4、 查询Score表中成绩在60到80之间的所有记录。
--范围查询 比较运算符
select * from Score where Degree>=60 and Degree<=80
--between...and...
select * from Score where Degree between 60 and 80
--5、 查询Score表中成绩为85，86或88的记录。
select * from Score where Degree=85 or Degree=86 or Degree=88
--离散查询
select * from Score where Degree in (85,86,88)
--6、 查询Student表中“95031”班或性别为“女”的同学记录。
select * from Student where Class='' or Ssex='女'
--7、 以Class降序查询Student表的所有记录。
--排序order by  升序asc 降序desc
select * from Student order by Class desc
--8、 以Cno升序、Degree降序查询Score表的所有记录。
select * from Score order by Cno asc,Degree desc
--9、 查询“95031”班的学生人数。
--个数count(*)
select Class,COUNT(*) from Student group by Class having Class=95031
select count(*) from student where class=''
--10、 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）
--子查询
select Sno,Cno from Score where Degree=(select max(Degree) from Score)
--降序取第一条数据
select top 1 Sno,Cno from Score order by Degree desc
--11、 查询每门课的平均成绩。
--平均分用avg(列)
select Cno,AVG(Degree) as '平均分' from Score group by Cno
--12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
--模糊查询 like  分组 group by...having...
select Cno,AVG(Degree) as '平均分' from Score group by Cno having COUNT(Cno)>=5 and Cno like'3%'
select avg(degree) from score where cno like'3%' group by cno having count(*)>=5
--13、查询分数大于70，小于90的Sno列。
--范围查询
select Sno from Score where Degree>70 and Degree<90
select Sno from Score where Degree between 70 and 90
--14、查询所有学生的Sname、Cno和Degree列。
--连接查询
select Student.Sname,Cno,Degree from Student,Score where Score.Sno=Student.Sno
--join...on...
select Sname,Cno,Degree from Student join Score on Student.Sno=Score.Sno
--15、查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,Degree from Course,Score where Score.Cno=Course.Cno
select Sno,Cname,Degree from Score join Course on Score.Cno=Course.Cno
--16、查询所有学生的Sname、Cname和Degree列。
select Sname,Cname,Degree from Student,Course,Score where Student.Sno=Score.Sno and Course.Cno=Score.Cno
--17、 查询“95033”班学生的平均分。
select Class='',AVG(degree) as '平均分' from Score join Student on Score.Sno=Student.Sno and Class=''
select avg(degree) from score where sno in(select sno from student where class='')
--18、 假设使用如下命令建立了一个grade表：
create table grade
(
    low  int,
    upp  int,
    rank  varchar(1)
)
insert into grade values(90,100,'A')
insert into grade values(80,89,'B')
insert into grade values(70,79,'C')
insert into grade values(60,69,'D')
insert into grade values(0,59,'E')
--现查询所有同学的Sno、Cno和rank列。
select Sno,Cno,Degree,rank from grade join Score on Score.Degree  between low and upp
select sno,cno,rank from score,grade where degree between low and upp
--19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。
select * from Score where Degree>(select Degree from Score where Cno='3-105' and Sno='') and Cno='3-105'
select * from Student join Score on Student.Sno=Score.Sno where Cno='3-105' and Degree>(select Degree from Score where Cno='3-105' and Sno='')
--20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。
--反向查询没有出现过得值not in
select * from score a where sno in (select sno from score group by sno having count(*)>1) and degree <(select max(degree) from score b where b.cno=a.cno)
select * from Score where Sno in(select Sno from Score group by Sno having COUNT(Sno)>=2 )and Degree not in( select max(Degree) from Score group by Cno)
--21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select * from Score where Degree>(select Max(Degree) from Score where Sno='')and Cno='3-105'
--22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
--获取年year(时间日期)
select Sno,Sname,Sbirthday from Student where YEAR(Sbirthday)=(select year(Sbirthday) from Student where Sno='')
select Sno,Sname,Sbirthday from Student where year(Sbirthday)=(select year(Sbirthday) from Student where Sno='')
--23、查询“张旭“教师任课的学生成绩。
select * from Score where Cno=(select Cno from Course where Tno=(select Tno from Teacher where Tname='张旭'))
--24、查询选修某课程的同学人数多于5人的教师姓名。
select Tname from Teacher where Tno=(select Tno from Course where Cno=(select Cno from Score group by Cno having COUNT(Cno)>5))
select Teacher.Tno,Tname,Cno,Cname from Teacher join Course on Teacher.Tno=Course.Tno where Tname in (select Tname from Teacher where Tno in (select Tno from Course where Cno in (select Cno from Score group by Cno having count(Cno)>=5)))
--25、查询95033班和95031班全体学生的记录。
--与 or
select * from Student where Class='' or Class=''
--26、查询存在有85分以上成绩的课程Cno.
select distinct Cno from Score where Degree>85
--27、查询出“计算机系“教师所教课程的成绩表。
select * from Score where Cno in (select Cno from Course where Tno in (select Tno from Teacher where Depart='计算机系'))
--28、查询“计算机系”与“电子工程系“depart不同职称prof的教师的Tname和Prof。
--联合查询
select tname,prof from teacher where depart='计算机系' and prof not in(select prof from teacher where depart='电子工程系')
union
select tname,prof from teacher where depart='电子工程系' and prof not in(select prof from teacher where depart='计算机系')
--相关子查询
select Tname,prof from Teacher a where Prof not in (select Prof from Teacher b where a.Depart!=b.Depart)
--29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select Cno,Sno,Degree from Score where Cno='3-105' and Degree >(select MAX(Degree) from Score where Cno='3-245') order by Degree desc
--any 列表中任意一个相当于max
select * from score where cno='3-105' and degree>any(select degree from score where cno='3-245')
--30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
select * from Score where Cno='3-105' and Degree >(select MAX(Degree) from Score where Cno='3-245')
--31、查询所有教师和同学的name、sex和birthday.
--联合查询
select Tname as name,Tsex as sex,Tbirthday as birthday from Teacher
union
select Sname,Ssex,Sbirthday from Student
--32、查询所有“女”教师和“女”同学的name、sex和birthday.
--联合查询 条件查询
select Tname as name,Tsex as sex,Tbirthday as birthday from Teacher where Tsex='女'
union
select Sname,Ssex,Sbirthday from Student where Ssex='女'
--33、查询成绩比该课程平均成绩低的同学的成绩表。
select * from Score a where Degree <(select AVG(Degree) from Score b where a.Cno=b.Cno)
--34、查询所有任课教师的Tname和Depart.
select Tname,Depart from Teacher
--35、查询所有未讲课的教师的Tname和Depart.
select Tname,Depart from Teacher where Tno not in (select Tno from Course where Cno in (select distinct Cno from Score))
--36、查询至少有2名男生的班号。
select Class from Student where Ssex='男' group by Class having COUNT(*)>1
--37、查询Student表中不姓“王”的同学记录。
--不像not like
select * from Student where Sname not like'王%'
select * from Student where Sname not in (select Sname from Student where Sname like '王%')
--38、查询Student表中每个学生的姓名和年龄。
--当前系统时间getdate(),获取数据库时间sysdatetime()
select Sname as '姓名',YEAR(GETDATE())-YEAR(Sbirthday) as '年龄' from Student
--39、查询Student表中最大和最小的Sbirthday日期值。
--最大值max（列）最小值min（列）
select MAX(Sbirthday) as '大',MIN(Sbirthday) as '小' from Student
--40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
--多个条件进行排序用，连接
select * from Student order by Class desc,Sbirthday desc
--41、查询“男”教师及其所上的课程。
select Teacher.Tno,Tname,Tsex,Cno,Cname from Teacher,Course where Teacher.Tno=Course.Tno and Tsex='男'
--42、查询最高分同学的Sno、Cno和Degree列。
select * from Score where Degree=(select MAX(Degree) from Score)
--43、查询和“李军”同性别的所有同学的Sname.
select Sname from Student where Ssex=(select Ssex from Student where Sname='李军')
--44、查询和“李军”同性别并同班的同学Sname.
select Sname from Student where Ssex in (select Ssex from Student where Sname='李军') and Class in (select Class from Student where Sname='李军')
--45、查询所有选修“计算机导论”课程的“男”同学的成绩表。
select * from Score where Cno in (select Cno from Course where Cname='计算机导论') and Sno in (select Sno from Student where Ssex='男')