查询语句需要考虑的：
1.先看要查询的属性是什么
2.看这些属性在哪些表里
3.如果的在多个表里，要看怎么连接
4.要看看题目有什么其他的条件
student表
score表
course表
teacher表
grade表
建表
CREATE TABLE STUDENT
(SNO VARCHAR(3) NOT NULL,
SNAME VARCHAR(4) NOT NULL,
SSEX VARCHAR(2) NOT NULL,
SBIRTHDAY DATETIME,
CLASS VARCHAR(5))
go
CREATE TABLE COURSE
(CNO VARCHAR(5) NOT NULL,
CNAME VARCHAR(10) NOT NULL,
TNO VARCHAR(10) NOT NULL)
go
CREATE TABLE SCORE
(SNO VARCHAR(3) NOT NULL,
CNO VARCHAR(5) NOT NULL,
DEGREE NUMERIC(10, 1) NOT NULL)
go
CREATE TABLE TEACHER
(TNO VARCHAR(3) NOT NULL,
TNAME VARCHAR(4) NOT NULL, TSEX VARCHAR(2) NOT NULL,
TBIRTHDAY DATETIME NOT NULL, PROF VARCHAR(6),
DEPART VARCHAR(10) NOT NULL)
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华'
,'男' ,1977-09-01,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明'
,'男' ,1975-10-02,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽'
,'女' ,1976-01-23,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军'
,'男' ,1976-02-20,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳'
,'女' ,1975-02-10,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君'
,'男' ,1974-06-03,95031);
GO
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论',825)
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,100);
GO
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-245',86);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
GO
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');
create table grade
(low smallint,
upp smallint,
rank char(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')查询语句练习题
--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。
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。
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
--6、 查询Student表中“95031”班或性别为“女”的同学记录。
select * from student
where class='95031' or ssex='女'
--7、 以Class降序查询Student表的所有记录。
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。
select count(*)
from student
where class='95031'
--10、查询Score表中的最高分的学生学号和课程号。
select sno,cno
from score
where degree=(
select max(degree)
from score
)
--11、查询‘3-105’号课程的平均分。
select avg(degree)
from score
where cno='3-105'
--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。
select avg(degree)
from score
where cno like '3%'
group by cno
having count(sno)>=5
--13、查询最低分大于70，最高分小于90的Sno列。
select sno
from score
group by sno
having min(degree)>70 and max(degree)<90
--14、查询所有学生的Sname、Cno和Degree列。
select sname,cno,degree
from student ,score
where student.sno=score.sno
--15、查询所有学生的Sno、Cname和Degree列。
select student.sno,cname,degree
from student,score,course
where student.sno=score.sno
and score.cno=course.cno
--16、查询所有学生的Sname、Cname和Degree列。
select sname,cname,degree
from student,score,course
where student.sno=score.sno and
score.cno=course.cno
--17、查询“95033”班所选课程的平均分。
select avg(degree)
from student,score
where student.sno=score.sno and
class='95033'
--18 查询所有同学的Sno、Cno和rank列
（可以不使用等值连接）
select sno,cno,rank
from score,grade
where score.degree between grade.low and grade.up//因为是等级
--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 cno='3-105'
and degree>(
select max(degree)
from score
where sno='109' )
--20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
select * from score a
where degree !=(select max(degree) from score b )
and sno in (select sno from score group by sno having count(sno)>1)
--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。
--这里all和直接查找最大值比较是一样的
select * from score
where degree>all(
select degree
from score
where sno='109' 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。--year,month,day
select sno,sname,sbirthday
from student
where year(sbirthday)=(
select year（sbirthday）
from student
where sno='108')
--23、查询“张旭“教师任课的学生成绩。
select degree,sno
from course,score,teacher
where course.cno=score.cno and course.tno=teacher.tno and 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,student,score,course
where teacher.tno=course.tno and course.cno=score.cno
group by tname
having count(*)>5
--25、查询95033班和95031班全体学生的记录。
select * from student
where class='95033' or class='95031'
--26、查询存在有85分以上成绩的课程Cno.
select cno
from score
group by cno having max(degree)>85
--27、查询出“计算机系“教师所教课程的成绩表。
select teacher.tno ,degree
from teacher,score,course
where teacher.depart='计算机系' and score.cno=course.cno and course.tno=teacher.tno
--28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。（还可以并集减交集）
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')
--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 sno,cno,degree
from score
where degree > any(
select degree from score where cno='3-245')
and cno='3-105'
order by degree desc
--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 cno,sno,degree
from score
where cno='3-105'and degree>all(select degree from score where cno='3-245')
--31、查询所有教师和同学的name、sex和birthday.
select sname,ssex,sbirthday
from student
union
select tname,tsex,tbirthday
from teacher
--32、查询所有“女”教师和“女”同学的name、sex和birthday.
select sname,ssex,sbirthday
from student
where ssex='女'
union
select tname,tsex,tbirthday
from teacher
where tsex='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.（注意是任课教师）
select tname,depart
from teacher,course
where teacher.tno=course.tno
--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 distinct tno
from course )
--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(ssex)>=2
--37、查询Student表中不姓“王”的同学记录。
select * from student
where sname not like '王%'
--38、查询Student表中每个学生的姓名和年龄。
select distinct sname,2019-year(sbirthday)
from student
--39、查询Student表中最大和最小的Sbirthday日期值。
select min(sbirthday)
from student
union
select max(sbirthday)
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。
select * from student
order by class desc,sage desc
--41、查询“男”教师及其所上的课程。
select tname ,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 sno,cno,degree
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=(
select ssex
from student
where sname='李军')
and
class=(
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 degree
from student,score,course
where student.sno=score.sno and score.cno=course.cno and cname='计算机导论'and ssex='男'