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')
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