Mysql 查询练习

CREATE DATABASE QueryExercise;
USE QueryExercise;
#建学生信息表student
CREATE TABLE student
(
sno VARCHAR(20) NOT NULL PRIMARY KEY,
sname VARCHAR(20) NOT NULL,
ssex VARCHAR(20) NOT NULL,
sbirthday DATETIME,
class VARCHAR(20)

);
#建立教师表
CREATE TABLE teacher
(
tno VARCHAR(20) NOT NULL PRIMARY KEY,
tname VARCHAR(20) NOT NULL,
tsex VARCHAR(20) NOT NULL,
tbirthday DATETIME,
prof VARCHAR(20),
depart VARCHAR(20) NOT NULL

);
#建立课程表course
CREATE TABLE course
(
cno VARCHAR(20) NOT NULL PRIMARY KEY,
cname VARCHAR(20) NOT NULL,
tno VARCHAR(20) NOT NULL,
FOREIGN KEY(tno) REFERENCES teacher(tno)

);
#建立成绩表
CREATE TABLE score
(
sno VARCHAR(20) NOT NULL,
FOREIGN KEY(sno) REFERENCES student(sno),
cno VARCHAR(20) NOT NULL,
FOREIGN KEY(cno) REFERENCES course(cno),
degree DECIMAL

);

#添加学生信息
INSERT INTO student VALUES('108','曾华','男','1977-09-01','95033');
INSERT INTO student VALUES('105','匡明','男','1975-10-02','95031');
INSERT INTO student VALUES('107','王丽','女','1976-01-23','95033');
INSERT INTO student VALUES('101','李军','男','1976-02-20','95033');
INSERT INTO student VALUES('109','王芳','女','1975-02-10','95031');
INSERT INTO student VALUES('103','陆君','男','1978-06-03','95031');

#添加教师表
INSERT INTO teacher VALUES('804','李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO teacher VALUES('856','张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO teacher VALUES('825','王萍','女','1972-05-05','助教','计算机系');
INSERT INTO teacher VALUES('831','刘冰','女','1977-08-14','助教','电子工程系');

#添加课程表
INSERT INTO course VALUES('3-105','计算机导论','825');
INSERT INTO course VALUES('3-245','操作系统','804');
INSERT INTO course VALUES('6-166','数字电路','856');
INSERT INTO course VALUES('9-888','高等数学','831');

#添加成绩表
INSERT INTO score VALUES('103','3-245','86');
INSERT INTO score VALUES('105','3-245','75');
INSERT INTO score VALUES('109','3-245','68');
INSERT INTO score VALUES('103','3-105','92');
INSERT INTO score VALUES('105','3-105','88');
INSERT INTO score VALUES('109','3-105','76');
INSERT INTO score VALUES('105','9-888','91');
INSERT INTO score VALUES('109','9-888','78');
INSERT INTO score VALUES('101','3-245','88');
INSERT INTO score VALUES('107','3-245','77');
INSERT INTO score VALUES('108','3-245','67');
INSERT INTO score VALUES('108','3-105','73');
INSERT INTO score VALUES('101','9-888','65');
INSERT INTO score VALUES('108','9-888','78');

#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 depart FROM teacher
GROUP BY depart;

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;

SELECT * FROM score
WHERE degree IN (86,86,88);
#6、 查询Student表中“95031”班或性别为“女”的同学记录。
SELECT * FROM student
WHERE class='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(class) FROM student
WHERE class='95031';
#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）
SELECT sno,cno FROM score
WHERE degree=(
    SELECT MAX(degree) FROM score
);

SELECT sno,cno FROM score
ORDER BY degree DESC LIMIT 0,1;
#11、查询每门课的平均成绩。
SELECT cno,AVG(degree) 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。
SELECT cno,AVG(degree) FROM score
WHERE cno LIKE '3%'
HAVING COUNT(1)>=5;
#13、查询分数大于70，小于90的Sno列。
SELECT sno FROM score
WHERE degree>70 AND degree<90;
#14、查询所有学生的Sname、Cno和Degree列。
SELECT a.sname,b.cno,b.degree FROM student a,score b
WHERE a.sno=b.sno;
#15、查询所有学生的Sno、Cname和Degree列。
SELECT a.sno,b.cname,c.degree FROM student a,course b,score c
WHERE a.sno=c.sno AND c.cno=b.cno;
#16、查询所有学生的Sname、Cname和Degree列。
SELECT a.sname,b.cname,c.degree FROM student a,course b,score c
WHERE a.sno=c.sno AND c.cno=b.cno;
#17、查询“95033”班学生的平均分。
SELECT a.class,AVG(b.degree) FROM student a,score b
WHERE a.sno=b.sno AND class='95033';
#18、查询男女比例
SELECT ssex AS '学生',CONCAT(COUNT(ssex)/(SELECT COUNT(1) FROM student)*100,'%') AS '百分比' FROM student
GROUP BY ssex;

SELECT tsex AS '老师',CONCAT(COUNT(tsex)/(SELECT COUNT(1) FROM teacher)*100,'%') AS '百分比' FROM teacher
GROUP BY tsex;
#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 sno FROM score
WHERE cno='3-105'
AND degree>(
    SELECT degree FROM score
    WHERE sno='109' AND cno='3-105'
);
#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 cno='3-105'
AND degree>(
    SELECT degree FROM score
    WHERE sno='109' AND cno='3-105'
);
#22、查询和学号为108、101的同学同年出生的所有学生的Sno、Sname和Sbirthday
SELECT sno,sname,sbirthday FROM student
WHERE YEAR(sbirthday)=(SELECT YEAR(sbirthday) FROM student WHERE sno='101')
OR 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 * FROM score
WHERE cno=(
    SELECT cno FROM course
    WHERE tno=(
        SELECT tno FROM teacher
        WHERE tname='张旭'
    )
);

SELECT a.* FROM score a,course b,teacher c
WHERE a.cno=b.cno AND b.tno=c.tno AND c.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 IN(
    SELECT tno FROM course
    WHERE cno IN(
        SELECT cno FROM score
        GROUP BY cno
        HAVING COUNT(1)>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 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“不同职称的教师的Tname和Prof。
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'
)
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o#和Degree,并按Degree从高到低次序排序。
SELECT * FROM score a
WHERE (
    SELECT degree FROM score b
    WHERE cno='3-105' AND b.sno=a.sno
)>=(
    SELECT degree FROM score c
    WHERE cno='3-245' AND c.sno=a.sno
)
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CnoD#egree.
SELECT cno,degree FROM score a
WHERE (
    SELECT degree FROM score b
    WHERE cno='3-105' AND b.sno=a.sno
)>(
    SELECT degree FROM score c
    WHERE cno='3-245' AND c.sno=a.sno
)
#31、查询所有教师和同学的name、sex和birthday.
SELECT sname,ssex,sbirthday FROM student;
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 a.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 tname NOT IN (
    SELECT tname FROM teacher t,course c,score s
    WHERE t.tno=c.tno AND c.cno=s.cno
);
#36、查询至少有2名男生的班号。
SELECT clas 3ff7 s FROM student
WHERE ssex='男'
GROUP BY class
HAVING COUNT(*)>=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 sname,(SELECT YEAR(CURRENT_DATE))-YEAR(sbirthday) AS'年龄' FROM student;
#39、查询Student表中最大和最小的Sbirthday日期值。
SELECT MAX(sbirthday) AS 最大,MIN(sbirthday) AS 最小 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。
SELECT * FROM student
ORDER BY class DESC,sbirthday ASC;
#41、查询“男”教师及其所上的课程。
SELECT tname,cname FROM teacher,course
WHERE tsex='男' AND teacher.tno=course.tno;
#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'
)
AND sname NOT IN ('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 sname NOT IN ('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 sno,degree FROM score
WHERE sno IN(
    SELECT sno FROM student
    WHERE ssex='男'
)
AND cno IN(
    SELECT cno FROM course
    WHERE cname='计算机导论'
);